I'm disappointed Arteta wasn't smart enough to see what I see very clearly now: Martinez is the far, far stronger character, 10 times better at commanding his box, and a much better fit with the way Arteta wants to play out from the back. Leno is absolutely terrible at that short passing game and always has been (at Arsenal), in my opinion. He can kick very well, that has never been the issue (again at Arsenal anyway), but his touch, weight of passing, confidence under pressue, speed of thought, pass selection - they're all lacking horribly, and make him unsuitable as our goalkeeper.
Hindisght is a wonderful thing, and we fans had to rely on that to an extent because we hadn't see enough of Martinez at that time. But Arteta worked with him for 9 months (although, thinking about it, lockdown did take up a lot of that), and the FA cup run should have been enough for Arteta to realise that Martinez was the guy to hang your hat on. He got it wrong, and we lost a very good goalkeeper that is Arsenal through and through. Very disappointing.