I like FFX-2 cause its so...different. I've only got one of the endings though so I need to see them all (namely the 100% one) to place my judgement on it. But the one thing I have decided hands down is that FFX-2 has the best battle system IMO.

As far as being "necessary", the answer is ummm...no, I don't think so, but who gives a crap, most sequels arn't "necessary".

I think too many people are afraid of seeing something different for a change *sigh*.