I agree he's lost some legs, but why aren't we playing him like a 32 y/o? Is there another 32 year old box to box midfielder at the highest level who plays 180 minutes a week?
He should be playing every other game and if we did that I genuinely think we'd see his performances shoot back up to something approaching his best, because the mind is willing, but the body isn't able to do that role anymore - and things like sprinting back into position, or a lapse in concentration when you're marking are the first things to happen when you're knackered.
I still think the best thing the club could do this summer is to offer him a bench role at a much reduced wage. If he doesn't want it, fine, but if his ego could take the bit part role, he'd be a force of nature to bring off the bench - in practically any scenario because as both an attacking substitution to get a goal or trying to choke out a game with possession, he'd be fantastic.
And he's clearly a big leader in the dressing room as well as on the pitch, you can see that from the way the other players speak of him, and if the personal relationship is OK, having a player who is familiar with Guardiola's training methods would be a bonus too.