Teams firstly need to be attacking-minded to expose weak defences - something all BL sides are.
Whilst that is true, the games i saw teams didn't need to be that attack minded as the defenders just let them through.
Maybe it is down to the fact the German league has had a diving problem for ages so defenders are taught at an early age not to tackle. Then when they get to the top league they suddenly find themselves in trouble when they have to do it.
Some of the marking was down to a lack of communication or the set up was plain wrong. Hopefully teams can sort this but i honestly doubt more than two of the teams have defenders capable of doing it.