Darth Lucas said:

But I like the idea that he could be even more powerful than Palpatine ever was. So much so that he was able to deceive Palpatine in believing him to be dead while he waited for the perfect moment to rise up. It's something that could be extremely cool if it was done well and would actually give the prequels SOME kind of purpose in this saga besides pointlessly setting up the OT and pissing off alot of fans.

I would hate it if the new villain was "more powerful than palpatine ever was". That would cheapen the movies that came before it IMHO, and sequels should never cheapen the originals.