I'd imagine the Arsenal fans won't be too mad. Not like I have my pulse on the opinion of a bunch of people an ocean away, but practically everyone must know his status as a Barcelona trainee, his family's ties to Barcelona, and what the team means to Basque players, as it's all been repeated in the media ad nauseum.
This wasn't a player wanting away for a new contract, which would have gotten a different sort of reaction.
If anything, I think there's a gradual disgruntlement growing at Wenger's refusal to compete with Chelsea and Man U in terms of spending. I'd throw Man City in there, but nobody's going to keep up with that.