Has nothing to do with stat inflation, and everything to do with genre emulation. In the comics (at least, until Keith Giffen and JMD poked fun at it), even the out of shape supers are still incredibly good at what they do. They're simply better than "normal" folks, even if they're supposed to be normal themselves. Its part of what makes them superheroes and not just a schmuck in a spanex outfit.
So yeah, Pulsar is a high school dropout (and that, btw, doesn't necessarily reflect a lack of intelligence), but is still fairly bright. Or Witchcraft can actually be really dexterous, despite a lifetime spent in study. Why? Because it makes them more heroic... they're cut from better cloth than the average person.
Stat inflation, I think, is something that happens when people try to one up each other or their opponents with out regard to character concept. Witchcraft is DEX 20... which is on the low end of DEX in the CU, and fits the character and genre. However, if she's DEX 28 (and thus better than nearly anyone else on the team), while still supposedly a bookworm... that's stat inflation.
The key is to compare the characters to other characters at their power level, not to the mooks and red-shirts they're supposed to beat up.