Everything you describe here can be sorted out by a top class manager, motivation, work rate, crossing, passing etc
Some players would have to be moved on as they're not good enough, but others could improve a lot with proper training, as for motivation much of that comes from the way the manager handles players.
If a player can't do something well, then you get him to practice a lot and he'll improve....our training/coaching is sh*t as has been shown in recent years.