Yeah, but he did actively improve those two already amazing teams. He sold off ageing superstars at Barca and ultimately replaced them with kids from the the academy.
The 4-3-3 where the central defenders split, the defensive midfielder drops deep, and the full-backs plough forward became very in vogue after him.
I would have loved to see him move to more of a "project" club, but if the situations had been reversed would anyone care? If he'd started at some mid-table La Liga team and got them into the UEFA Cup beforehand would that have legitimised him? He got the Barca B team promoted, if that means anything to you. No-one really talks about Wenger at Monaco, Klopp at Mainz etc. etc.