In the CL did he certainly flop big time, no Messi to bail him out. But I think it's fair to say he's a good coach in the national league, although only after spending 1 billion or more lol.
In Barca did he take over one of the greatest teams of all time, in Bayern did he take over a treble team that was well drilled all over both tactically and physcially, in England did he take over some obscure oil club with endless funds to get him all the players he wanted.
It's fair to say he never had to really fight in those clubs where he been in charge, everything was served to him on a platter with only few exceptions maybe when he took over in Barca during the first year.