Getting back on topic, I do think it would be a good idea to have more than 2 possible endings, not nesesaraly light, dark or neutral. Here are some of my thoughts for alternative endings to the first game.
Revan Sacrifices self to destroy Star Forge.
Malak pursuaded to repent/join Revan.
DS Bastilla stabs Revan in the back and takes Star Forge.
DS Revan chooses to kill Bastilla. As a result the republic fleet destroy Revan and the Star Forge even though Malak is defeated.
The republic capture the Star Forge intact and it's dark side power starts to corrupt them (Revan could have the option of activating the self destruct).
Revan reprograms the Star Forge droids to kill Malak, but they get out of control and destroy both the republic and the Sith.