I don't think it should have been mentioned during the season, but there's plenty of time it could have been cleared up in prior to now. What leads me to believe his mind has been made up all along, however, is the fact that it's taken for him until now to come out and say that the club is not moving forward fast enough and that he doesn't share the visions of Wenger and the Directors...despite the fact that they've made two of the largest signings in their recent history in the last month or so...what more could they have done to persuade him that the club has ambition?
I suppose if Arsenal have been aware of this all along, then that wouldn't be so bad, but the impression one gets from reading the recent interviews of Wenger is that this isn't the situation.