How about putting Nihilis back on Malachor then, and have just the finest battles of all time raging all over the system? I killed off Nihilis and then remember thinking after that, "I have to do _another_ planet? I thought Nihilis was It--is there really something worse than a planet-consuming monster?" So, I too felt like Malachor in some ways was anticlimactic, because Traya just didn't have the same 'bad' feel as someone who sucks the life out of entire planets.
bcarlock