Most of these are decent players and it is not their own fault if things don't work out. Fitting into your style of play is not necessarily that easy and also it depends on what quality is around you. Leaving from a club where you had success doesn't mean you will be a perfect fit and achieve the same results. Look at United you could throw in any top player into that team and they will look bad. A player is only as good as the players around him and if they are prepared to change. Lukaku was never going to fit into Chelsea's playing style and was a stupid purchase.