Ooh u cheeky bastard with facts. Well Bayern is the main "threat" ofc and can't see any club in English football close to them tbh (Frank will say that chelsea is above them for sure). But your list ends after the 13/14 group stage, after that Bayern beat United 4-2 on aggregate without a loss and Arsenal 3-1 and the season after that Bayern did lose a game to City in the group stage but won the group nonetheless but this is only Bayern and as you already stated they are the main threat.
But Dortmund have given english sides hard times and Leverkusen have snatched a win here and there, recently away to Spurs. Schalke have probably mostly got beaten and this year Gladbach lost and drew against City (right?). I should have maybe put 2010- in my post cos before that English teams were indeed a lot more superior than the German teams.
Considering that Bundesliga is such an easy league and Bayern could win it with their B squad according to people who doesn't watch the games it's quite surprising that the mighty Premier League teams nowadays are having a hard time against them in the CL. If for example Leverkusen or Dortmund played against any of the top teams in England, I wouldn't mind betting on them winning.
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Well I'm studying physics so I'll take that sarcasm as a compliment I'm rooting for Arsenal in the Premier League and after Bayern so I too hate when they lose against a bundesliga team (except for Bayern) but it's nice that the Bundesliga is silencing some of the critics ^^