We haven't even seen Joe play under Pep yet, not in a serious match, and yet he's somehow fallen short of the standards required! I could understand this line of argument if we'd played 6-10 games and it had become an issue in matches.I'd be less inclined to panic if I had Barca or Bayern's defence in front of me!
I'd say if the keeper being able to play the ball out from the back is integral, then so is the defence he's playing it out too - which includes Clichy and Kolarov. I'd say every single position on the pitch is integral to the system. 5-10% down will probably lose you the league in the PL. Probably not in Germany.
I don't think Joe's the weakest link, but if an opportunity arises to upgrade in his position, yes, we should take it - sometimes, it's all about timing / opportunity. But if there's a specific focus on a keeper upgrade ahead of all else, then that would be a worry (to me).
And as much as Hart is criticised for his distribution (which I do often!) - I've seen plenty of times when's he's been looking to distribute early and the rest of the team showing little urgency - and thus the opportunity is gone (i.e. it's not ALL his fault!).
If we're going to play it out from the back as a matter of course - there's not much point in Joe playing it to Kolarov / Clichy / Mangala etc unless they are equally as comfortable with it, and I'm not sure they are.
The pre-season game vs Arsenal is not a benchmark because the back 4 were giving the ball away in that game. A keeper is not going to pass it to his back 4 if they are under pressure and are struggling with their own game.