For those who had realistic expectations, Fleury is probably developing at a reasonable pace.
Ideally, he would have spent that first year after getting drafted with Cape Breton. Last year he could have started his professional career, continue it with WBS this season, and finally be the backup for Pittsburgh next season before taking the starting job in '06-'07. So in his fifth year after being drafted, he would be ready to be the starter-- that's probably a reasonable timeframe for talented goalies that aren't superhuman (Lehtonen).
Instead, that first year where Fleury bounced around from team to team was kind of a waste, largely due to bad management in Pittsburgh. But I'd say things are still on track for Fleury. Let him start this season in WBS (which is undoubtedly the right move), be the backup next season, and then assume the starting job in '06-'07.
Honestly, I don't think we should have expected Fleury to be all that further ahead in his development at this time. We were just impatient as fans, just as Penguins management was.
I think we should really worry about Fleury if he doesn't improve upon from last season.