I tend to run against the grain on characterization issues. For me having characters too well developed actually tends to make me identify/sympathize with them less that a medium level of development. When they throw a whole lot of effort into character (fresh on my mind is FFXIII) I tend to draw away from them. This is most likely because I tend to not like people in general.

In sprite and crude polygon based RPGs no matter how hard they tried to nail character there was always a significant amount left up to the imagination. I'm guessing the reason I could become so much more attached to these characters (which for me is the equivalent of not being repelled) is that I somewhat filled in the blanks with something that appealed to me. FFT is an extremely unique case where I can't think of a single character I didn't like. If they had huge long exposition dialog like is the standard nowadays I would probably have found something to dislike about all of them.

It was interesting that you brought up Mega Man because that is one series where I have become extremely attached to the characters, despite the fact that they have extremely little dialog. A sort of personality formed based on the little lines I had, their sprites/animations and what I wanted them to be. Sonic was also sort of like that, until they ruined the series post S&K3.