That was Apprentice Potter, I think. Harry proclaims that Snape basically helped produce a generation of incompetent boobs that can't function in the real world, because he's handed them everything on a silver platter, as they've come to expect from their generally privileged lives at home (Snape is a bit of an oddity as he came to Hogwarts as a poor half-blood barely tolerated by the Princes).

Another fic, which I admit is a bit bizarre, holds that magical conflict and situations of extreme duress in childhood build up magical resistance, and by deliberately slanting things as they are in Hogwarts, Dumbledore and Snape are conspiring to keep the Slytherins from developing the same level of magical strength as the Gryffindors.

But I'm getting a bit off the topic.