Hojo to me was the true villain of FF VII. He was the true mastermind and manipulator behind all the evil of Shinra, even moreso than Rufus. His twisted and corrupt ideas [and their execution] made everything possible, is ultimately responsible for Sephiroth.

Sephiroth was nothing more than a [weak] final boss you had to beat just because he had a bunch of power. What makes Sephiroth different than most FF villains is that he has no personality and virtually no characterization at all [even less than the Emperor from FF II], making his character completely uninteresting. In terms of raw power, he seems weaker in comparison to some of the other FF villains and certainly doesn't demonstrate any motivation. In FFAC he further demonstrates his lack of character and personality, and I'm further convinced he's just another generic woman-haired villain [are the Japanese ever going to get tired of this cliche?] that lacks a true goal ["sailing the cosmos like your mother"? Give me a break]. Sure his goals might sound grand, but they lack ambition and motivation in their own conception.

Of course this is just my opinion, but I personally found Kefka's "let's destroy everything" more interesting because of the character that it's attatched to. Most people here will probably disagree with me though.