I'm afraid I am no closer now then I was when I started this thread to know what the right answer is...
I'm afraid there
is no one "right answer". Believe me, I spent years going backwards and forward on ability generation methods and
never found one that sat quite right. Random methods seemed to alway give one PC much better or worse than the rest (or, most often, both), while point buy seemed to invariably give cookie cutter characters.
Eventually, my epiphany came in the realisation that, really, it didn't matter all that much. As long as everyone was having fun, and as long as no PC was
too dominant, then it all worked out okay. And so I started giving the choice.
(And that one case, where one PC was too dominant, turned out to be as likely due to optimisation and system mastery as good rolls. So point buy didn't actually help with that. So even in that case, the solution was more likely to be a quiet word with that one player, rather than re-jigging the stat generation method
again in pursuit of a holy grail that doesn't seem to exist.)