I know what you mean about them being fragile at times but I do find that is sometimes partly due to the fact there is very little defensive support from the midfield, weather that be in the centre or the wide players not tracking runs and the full backs being left exposed. The defence certainly need to tighten up though.
individually they are all good players but would like a brute of a centre back and mchardy pushed further forward. legs in centre mid, pace out wide and a presence up front to play alongside hester is a must