I get what your saying, im not disagreeing with you, but I don't think its a case of him holding "all the cards", as he still has a contract
If he's out of contract then obviously he does
Arsenal will surely still have a say in where he goes - every club in Europe would want him
If arsenal play hardball and it gets messy, then he may have to go to his second choice team, its a gamble for them though
Arsenal have got no say in where he goes. They either let him go where he wants, or he stinks the place out for a year having hissy fits and then leaves them £40m poorer. And we all know he's a player who makes sure everyone knows when he's unhappy.
Everyone knows Arsenal won't let him go for free so everyone knows any "hardball" would just be a bluff.