Arsenal Midfield

Midfield been a major strength of Arsenal, and obviosuly you still have Fabregas, easily one of the best there is. BUT, you have lost Hleb, Flamini (good performer last season) and potentially Gilberto. Now I have seen a few snippets of the youngsters/reservce, and it seems to me that Diaby gives cause for optimism, and then of course you have Nasri, who looks to be good, but as always, there's the issue of acclimatising to the EPL.
It seems to me that Mr W has an ability to make his midfield work, regardless of who is in it, or what formation they play, so possibly there is no big deal, but am I right in thinking that there is a perceived weakening of the midfield?