Agreed.
Malak, Revan, Bastila, HK-47, Mission, the various Sith soldiers, etc would all make terrific figures. And that's just from the first game!
Darth Nihilus, Sion, Traya/Kreia and Visas would all be musts for me, too.
And after reading the DARTH BANE novel (tremendous... and this is coming from someone who thinks 95% of the EU is garbage) he and a few of those characters would be awesome as well.
Seriously, if SSC wants to beef up the "Lords of The Sith" line past the films they should begin and end with KOTOR. Heck, as much as I kinda dig Asaaj Ventress, I'd rather have any of the aforementioned KOTOR characters before her.