Try swapping your players round on your next training day. Putting players in different positions than they normally play, this lets them appreciate the techniques required by different players and helps them understand each others difficulties.
It also helps players perfect new techniques which can only enhance their game because when your on the backfoot you need all the tools you can to pull that game back.
another important thing to remember is to keep a training day for learning and improving skills. Don't let it deteriate into a free for all.
If you want to play, practice a few skills, put them into practice, review your findings and practice some more.
As for paint hosing markers at the back don't worry about it. If a players comfortable with a position, he can play better with a low end marker there than a less skillfull player with a top end marker.
If a players enjoying there game They'll be wanting to upgrade and be happier doing it than if they feel like they have been forced to,
Apologies for the long post, I got on a rant
JJ