I have agree on Diaby. I am pretty sure that if he had been able to be helthy all year that we would be higher up the table. As it stands all evidence points to a player who will more often than not be unavailable, something we can not afford with out thin squad.
Personally I am an Arshavin fan however if we are going to continue to try to play him out of position on the flanks we might as well sell him.
I think Carzorla is over used and at danger of fading badly over the second half of the season to avoid this from happening we should play either Rosicky or Arshavin in his role. Arshavin is probably the only other player we have who can match Carzorla's creativity when played in the middle on a free assignment with Rosicky not far behind. Ramsey is not that guy.
M'vila and or Biglia are badly needed because as much as I like Arteta, if we take for granted the Wilshire-Carzorla combination, I would prefer a more physical presence to help these two smaller type players.
Finaly we do need a keeper who can earn us some points and Szcsesny is not that keeper. I was very hopeful when he first came into the squad and his size, presence and confidence where a breath of fresh air after Fabianki but I have to say he seems to have rather slow reflexes and as result gets beaten (from outside the box) to easily and to often.
We have never really managed to replace Lehman. All great teams have a good keeper. Last year perhaps the difference between ManU and City was Joe Hart, had Van der Sar still been with Man U I doubt City would have won the title.