Can the OP just put the word *SPOILER* in this title cause I ain't using spoiler tags...
Anyway, I'm an wholly against the notion that the Entity is Kreia - mainly because I realise that BioWare are just going to do an epically poor job of portraying her and clearly do not understand her. It seems obvious that they interpreted her as an evil, dark side witch who just wanted revenge on everything, including the Force. And probably believe that for that reason she would become some sort of dark side entity and support the Emperor in his destruction of the universe.
How very wrong they are:
- Traya as hardly a darksider - in fact you could argue that she was redeemed by the time of her death. She was explicitly clear that to embrace either the light or the dark was to enslave yourself to flawed teachings, and instead encouraged a usage of both. If anything she was grey.
- Traya wanted to end the Force partly because it controlled people fates, but also because in exerting its will countless lives were lost, she wanted to preserve life. So if she knew of the Emperor's plans to commit genocide on a galactic scale she would hate every bone in his body.
But she could be lying when she was released, since she did that a lot in KOTOR2.