And now I just feel silly. At least I didn't argue the case any further.
Still holding onto my opinion to some extent when it comes to certain Skills, especially ME. It just doesn't seem right to me otherwise, given that the degree of sanity and the level of intellect seems to lessen as the rank goes up, but almost all EX-ranked ME's usually have a single obsession/complex but are otherwise close to sane (or at least seem sane-ish). There's also the weirder cases (which admittedly are outliers) such as Gilles, Raikou and Penthesilea.
Exceptions from the usual way of things are, of course, rare (and mostly ME-related).