Originally posted by Darth Angel
My problems with this are:1) As I said, the very sith knowledge that Sidious had access from the sith order himself should be far greater then whatever force religion he could find around the galaxy, which would mean that 99% of his dark side knowledge should already be in his possession before he became the emperor.
You're jumping back into the disposition of "random speculation" being canon when it suits your purposes. You don't get to throw an arbitrary number as to evaluate Palpatine's Force knowledge. The fact that the Sith and the Jedi were the most famous or largest Force wielding cults out there doesn't mean that they are necessarily the most knowledgeable or that Palpatine had access to the full scope of their knowledge until his ascension to Emperor, where he had the resources to collect them without detection.
2) Now, even if we can think that during his reign as emperor he gathered and extended his force knowledge, thus increasing his power (even though as I said before I hardly think he could have greatly extend his knowledge about the dark side), what kind of knowledge could have he got during the years post endor? I mean, hadn't he "gathered the works of millions of worlds"? So, what kind of knowledge could he got from ROTJ until the DE? In fact, the only thing I can think is the force storm, sure, he had now a new weapon (one he couldn't control though), but taking that, I see no other reason for him to become more powerful.
No one said that he became "tremendously powerful" between RotJ and DE; we said he became "tremendously powerful" from RotS to DE.