KotOR 2 didn't try to change a thing, it merely questioned everything previously established, that was the goal of the game, whilst pure good and pure evil can clearly be defined(The Jedi Order and the Sith Lords), that does not mean there can't be those who have other views on the force(Like Qui-Gon Jinn a G-canon character), it does not mean they conflict, but instead merely add to the many views and philosophies surrounding the force, the two we all know more than any, the two that are defined, are the orthodox Jedi Order's view and the Sith view(Which isn't really a view, it's always been seen as a path to power.
As far as Kreia goes, she admitted that perhaps all she was, was an old woman who had come to rely upon something she despised, but her blind hatred for everything Jedi and Sith wouldn't let her see that, instead she used any and all evidence she could find to support her argument, she was basically your typical internet arguer who is too proud to admit when she's wrong and grasps at any straws she can find, the sad thing about her is the fact that when she died, did she only realise that she was wrong and came to accept the force, it was kind of her redemption.
She had been a Sith the entire time, even Atton could see that, she just couldn't accept that.
"Young fool, only now, at the end, do you understand."
^^This, I agree with Rayla - KOTOR 2 wasn't saying Kreia was right, it just wanted to question what had already been established and make you think, and I like games that make you think. Your right to say however (OldVengeance) that Kreia was perhaps blinded by her hatred for the Force, but she had good reason, she had had her teachings rejected and her students taken from her, she was exiled from the Order, she witnessed the destruction of the Mandalorian Wars and Jedi Civil War, saw her best pupil fall and then when she finally turned the the dark side she was betrayed again. She's been through a lot, and has every reason to be bitter. But I think Rayla is right here in saying at the end she realised she was wrong, that the Force is necessary and in some way was 'redeemed', she did still believe that Jedi and Sith shouldn't be so reliant on the Force (not give it up, but don't depend on it so much and use it to solve everything).
I think this is a good message, after all wasn't it the arrogance of the Council, born from their fanatic dependence on the Force to show them what to do, that led to their apathy during the Mandalorian Wars? Those Jedi needed to learn that the Force isn't the answer to everything, it won't always show you what to do and it won't always solve ever problem. Sometimes you need to rely on yourself for guidance. I believe the Jedi learned this eventually from Meetra, and so have become the better Jedi that we know today.