Yeah, being a ridiculous psychopath should be a valid playstyle. That said, the morality system needs a bit of a facelift. There's really no point to being evil in Fallout most of the time. In fact, it can be harder to be evil than good in some cases. Being bad should be the easier choice, the kind of thing someone with a weak will would do. This is a wasteland where people struggle to survive day to day, so good and evil shouldn't necessarily be two equally viable options.
That depends on the type of *good* you might be doing, stealing is evil, right? No denying that, though it makes things easier, however, consider a situation in which a merchant is accosted by radscropions and you save him from them before he's killed, no matter whether he might have been able to kill them with or without your help, that's still a good thing to do, right? But you may not have done it for a good reason, as saving him and letting him go (not without appropriate reward, mind) back to wherever his home is, then you've gotten good reputation, and that's the only reason you may have saved him.
In that situation, you could probably have made it easier for yourself in the long run because you helped him, and it wouldn't have even been that hard, it would be kinda 'pragmatic villany'.
Honestly, a morality system would probably work better with a kind of X and Y graph, the Y is pragmatism while the X might just be your morals, so doing tons of little good things (like saving a caravan guy against things that really wouldn't give you any trouble) would only increase your moral level to a point, and at the same time increasing your pragmatism.
I don't know what I'm saying anymore.