Diaby will almost certainly see out his contract at Arsenal. I cant see Wenger just pushing him out. its not his style. The biggest problem we have is our wage structure. Wengers wage structure. It needs to be changed and changed VERY soon if we are to actually compete. Your list of players to leave is valid although Ramsey will only be going on loan (if he goes anywhere) He has just signed a long term contract and so will almost certainly be given another 2 to 3 years before his future is decided. Plus Rosicky I think is exactly what we need for depth. Yes he is injury prone, yet when fit he is a very good player and probably our best squad player. He is experienced and has class which I think is essential for quality in depth. I guess it depends on how long the contract he signed was last summer. I think it was 2 years. Arshavin and Squillaci are leaving in the summer as their contracts are finished, so at least we have that guarantee. Park Denilson and Djourou are not on your list who i believe should be on their way before Gerv, Ramsey and Rosicky.
I said elsewhere that as much as we want to see some players leave the only guarantees we have in the summer are Arshavin and Squillaci, the likely players to move on are Denilson, Djourou and Sagna. Unfortunately i think we will be stuck with Bendtner for his last year of contract and god knows who would want to buy Chamakh and Park. If we get rid of 5 or 6 players the only real definitely should be is that instead of replacing them all we should replace them with only 3 players. Change our wages structure and pay 3 good or very good players the wages they could demand elsewhere so that we can still attract them.