(CNN) -- Most fans would agree that a great football league needs some key ingredients: skilful players, excitement and drama on the pitch; and off the field, passionate supporters and owners who love and understand the game.
But these days soccer is also about big business, million-dollar deals and billionaire benefactors lining up to plow money into the game.
Those seeking a balance between these sometimes awkward bedfellows will often point to Germany and the Bundesliga. With two clubs in Saturday's Champions League final at London's Wembley Stadium, high attendances, keenly-priced season tickets, equitable club ownership and the national team on an upward trajectory, German football appears to be in rude health. But is it?
In the domestic Bundesliga, Bayern finished 25 points clear of Dortmund and 36 points ahead of fourth-placed Schalke 04. If Manchester United's path to the English Premier League title looked like a cakewalk, the German champions could have taken the entire dessert trolley along with them.
Arguably the competition is beginning to resemble anything but.
Writing in the German tabloid Bild last month, Bayern's former goalkeeper Oliver Kahn expressed fears that the domination of the Munich club and Dortmund -- Bundesliga champions in 2011 and 2012 -- is here to stay, and that the gulf at the top could widen even further in the future.
Even Dortmund's manager Jürgen Klopp has remarked that the league is in danger of becoming boring.
Arguably Dortmund were unable to mount an effective challenge this season as they saved their best performances for the Champions League.
But the brilliance of both Bayern and Dortmund in their respective semifinal wins against Real Madrid and Barcelona suggests the Bundesliga needs to be wary of an emerging duopoly.
It's not hard to see why Bayern and Dortmund have become so omnipotent both at home and abroad.
"Two great managers, two teams that almost mirror each other in the way they play, the way they attack, the way they defend without the ball," former Bayern midfielder Owen Hargreaves told CNN.
"Bayern have only conceded something like 15 goals, which is ridiculous in a full season," he added.
"At Dortmund, the average age is 23, and I think Jürgen Klopp has done such a remarkable job to take that group of players and virtually dominate some terrific European teams."
Yet among German fans there are concerns.
"Of course the current situation could become unhealthy," said Stuart Dykes, a Schalke season ticket-holder since 1988, and the supporter liaison officer project consultant at fan ownership campaigning body, Supporters Direct.
"Even Bayern, while obviously delighted to have won the title so comfortably, have talked about it not being in their interests to do it every year. Ultimately the overall product of German football would suffer."
Not content with running away with the Bundesliga this season, Bayern are already laying plans to dominate next season, notably with the appointment of former Barca coach Pep Guardiola -- who guided the Catalonia club to 14 trophies in four years -- to take over from Jupp Heynckes.
Dortmund's hopes of catching Bayern next season have been further jeopardized by the loss of playmaker Mario Gotze, who recently agreed to join the Munich club at the end of this season in a $56 million deal.
Rumors of a Bayern bid for the Bundesliga's second-highest scorer Robert Lewandowski, whose four goals against Real Madrid in the semis propelled Dortmund to Wembley, suggest a strategy centered on dismantling their only rivals' chances before next season has even begun.
The consolation for Dortmund fans is that at least the club has some money to spend to try to keep pace.
Eight years ago it was on the brink of financial ruin, missing rent payments on its stadium and facing crippling losses.
Extraordinarily, a loan from Bayern played a part in Dortmund's survival -- with $2.5 million handed over to help stave off bankruptcy.
Dortmund's path back to solvency and success has been paved by Klopp's highly astute signings, such as Poland striker Lewandowski, as well as his trust in talented graduates from the club's youth academy, like midfielder Nuri Sahin.
But it has been the club's willingness to part with its top players at the height of their value that has restored Dortmund's financial health.
Shinji Kagawa, signed for just $300,000 from the Japanese second division, was sold to Manchester United for $17 million, while Sahin joined Real Madrid for $12.8 million.
"Obviously (Dortmund and Bayern) have the power and the money to buy the best players as Bayern has done again; they've signed Götze for £37 million, and you know, the rich get richer, and that's just the way that football works," said Hargreaves.
"People can argue that's not fair, but they paid a lot of money to Dortmund -- and they can invest that money in younger players."
In England, the Premier League has taken a laissez-faire approach to regulating clubs' finances.
Alongside huge television deals -- the latest of which could see a record £5.5 billion ($8.3 billion) windfall in broadcasting income -- extraordinarily wealthy owners such as Chelsea's Roman Abramovich and Sheikh Mansour at Manchester City have been allowed to spend big for success.
But the model in Germany is very different.
Under the league's "50+1" rule, Bundesliga clubs must be controlled by their members -- with at least 50% of shares, plus one, in their hands.
This means a club cannot be taken over by private investors. At the last vote on changing this rule, back in 2009, only Hannover 96 voted to scrap it.
The German system is geared towards preventing the influence of a rich benefactor from skewing the competition, but some argue that it will only serve to perpetuate the status quo.
Hannover has now won concessions in its attempt to change the "50+1" rule, and these will allow sponsors with a long-term relationship with a club -- more than 20 years -- to take a stake in it.
However club fans are already protesting about these changes, perhaps anxious at the advantage such a move might give their rivals.
"The next five years will be interesting," said Dykes. "The rules have had exceptions to allow for the different ownership structures of teams like Bayer Leverkusen and Vfl Wolfsburg, but Hannover has argued that this leaves them at a disadvantage, and you can see why."
But how is a booming Bundesliga affecting German football further down the feeding chain?
In the former East Germany, far from the country's football powerbase, one lowly team's fortunes are being transformed by Austrian soft drink company Red Bull's takeover.
In 2009, Rasen Ballsport Leipzig (better known as RB Leipzig) became the fourth club in Red Bull's football portfolio, alongside Red Bull Salzburg of Austria, Red Bull Brasil, and the New York Red Bulls of the American MLS.
Formerly known as SSV Markranstädt, league regulations prevent the club using the Red Bull brand in its name, so it settled on RB Leipzig instead; but there is no ambiguity over the power driving it forward, with a reported planned $128 million investment to take the club to the Bundesliga by 2017.
After promotion in its first season, followed by two years in German football's fourth tier, its plans look to be on track as the club prepares to contest the playoffs for another promotion in June.
The club's stadium, the impressive 45,000 capacity Red Bull Arena, is certainly ready.
"We accept this rule," said RB Liepzig's managing director Ulrich Wolter, referring to the "50+1" rule.
"The intention of the rule is to secure the league's integrity against short-term investment, I think everyone understands that."
However, Wolter is frustrated at the resistance to RB Leipzig's owners.
"Red Bull is not a Russian oligarch, or an Arabian sheikh," he said. "We've shown elsewhere that we're about a strong, sustainable investment and commitment.
"Why is our way the wrong way? What is the difference between our approach and a club with 50 different sponsors delivering the same thing?"
Even so RB Leipzig's new investors have encountered resistance.
The pitch at its former stadium was attacked with weed killer not long after the takeover, and fans of other clubs can be less than welcoming.
"It's getting better," says Wolter. "We're proud of our family and spectators. We don't have 'ultras' and we don't need them. It's a friendly family atmosphere here, with men, women, children, pensioners, it's a different way."
Germany's often raucous fans are, however, part of the fabric of the Bundesliga experience.
The biggest obstacle to change in Germany may come from those very supporters, many of whom view the English Premier League with disdain, given that they see themselves at the center of a club's structure.
The Bundesliga boasts some of the world's finest stadia, and its commitment to safe standing areas has helped enable clubs to keep prices low, as well as creating the boisterously vibrant atmosphere that characterizes top-flight games.
But while the cheapest season tickets represent superb value, if fans turn up on match day looking for tickets then the story is rather different. "People are always talking about cheap tickets, but it can be misleading," says Dykes.
"Of course standing tickets are cheap, as you would expect; but once these go, and they're usually in demand, the ticket prices at the top end are broadly comparable to those in England."
In fact, at $88 the most expensive match-day ticket for Bayern is the same as that at Manchester City, for example -- and $9 more expensive than at Manchester United.
This year, partly in response to incidents of crowd trouble at games, there have even been whispers that the prized standing areas could be abolished.
"Standing is vital to low ticket prices, but also the atmosphere and the overall product of German football," said a skeptical Dykes.
"The league realizes that and I can't see the standing areas being given up. It would be difficult under German federal law to 'ban' them anyway, so I just can't see it happening."
The worry for other Bundesliga clubs must be that the success of Dortmund and Bayern could put them out of sight in the financial and playing stakes; last year Chelsea received an estimated $77 million from winning the Champions League, while beaten finalist Bayern pocketed $53.65 million.
Youth and prudence
However, the notion that a couple of teams might dominate their league is not confined to Germany.
"Spain's that way, the last three or four years the third or fourth place team, they still play Champions League and they're 30 points behind," said Hargreaves.
"A lot of people in Germany love Bayern and love Dortmund, in the same way as people (in England) love Manchester United or Chelsea," he added, "but there are a lot of people who root for the underdog as well. So I think, in a way, it's a fair balance."
And Dykes remains unconvinced that a tipping point has been reached.
"It's too early to be talking about a duopoly," he said. "Success comes and goes. If we're still talking about those two in a few years' time, or Bayern are still miles ahead, then it would be a worry.
"People look at that possibility and of course it could be bad, but why would it happen? Bayern have always spent big; Dortmund is an exceptional team, but where will they be in three years?
"Players lose form, get injured, things can change quite quickly. I'm not worried."
For Wolter, the key to success lies in a combination of youth and prudence.
"You look at a team like Freiburg, they have a good academy, a good coach; it's still possible (to be successful). The new television contract has also given clubs more money ... and these academies are profit centers," he says. "But it's not all about money. It's also about education, good background work."
Nevertheless, as Bayern and Dortmund take the field at Wembley, some may be wondering if, as well as a moment of national pride, this game might also mark a less welcome watershed in German football.