I have a feeling that the $300 Million number is way off base.
I sure hope so, otherwise whoever set the budget for this thing was insane.

All MMO's are big gambles whether they're directly competing with WoW or not... APB completely brought down Realtime Worlds, and they were going after the GTA market not the RPG'ers.
I also don't think it's necessarily correct to use KOTOR sales... a single player RPG... to extrapolate MMO sales (and it's also not that relevant to compare it to sales of an FPS). It really is two completely different markets. In the single RPG space, KOTOR was very successful relative to the market.
I was looking mainly at the built-in KOTOR fanbase, which appears to consist of roughly a million people. But you're right, people who enjoyed a single-player KOTOR game may not be into MMOs at all. I was just trying to define the franchise's popularity.
I like BioWare and I like the KOTOR games. I don't want to see them fail.