I know Özil is a pain in the arse some of the time, but I could never want a player with his awesome quality out the club the way I want Mustafi out. Apart from the fact that Özil when he turns it on is a world class player; his performance against Leicester was one of my favourite things of last season. It's a privilige to watch him play some times.
Keeping bad players at the club is a mistake. Full stop. However far you push them down the pecking order, they're there laying in wait, ready to screw you over. Usually when you can least afford it.
Mustafi, Jenkinson, Monreal (at CB now his legs are gone), Elneny and Mkhitaryan (fleeting moments of quality but not even close to enough to avoid making this list).
Kolasinac and Xhaka don't belong on this list because they add quality too, but they are too often plain bad for us and really should be moved on if we can upgrade on them or someone offers reasonable money for them.
The rest of them need to go regardless. Take a hit on them financially, get them out, otherwise they will cost us. We would genuinely be better off playing youngsters.