I personally regard VIII's cast as the weakest of all Final Fantasy titles, along with the cast of XII.
I mean, I liked Xell, and when I grew older and started another playthrough, I also thought that Quistis was quite okay, but.. well.
Rinoa is one of the most annoying FF heroines in my opinion.
When I think about my favorite FF characters, I automatically skip VIII, since the cast really isn't worth mentioning.