Bayern looks a level above any of the Spanish or Italian teams (not even going to mention QSG). Unless Liverpool (or City maybe?) have a good game against them, don't see anyone stopping them.
Thing is, Hoffenheim showed how to beat them (not rocket science). I'm looking around at these top teams and aside from Liverpool, nobody has pace to run behind their high line. It's a pretty easy tactic to imagine against this team, but it's crazy how none of the top teams have much pace up front aside from one. (Unless you want to count QSG as a top team)