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I doubt even if you did find a middle path, that she would have been okay with it then, not simply because as a character, she cannot see perfection in the main PC - or anyone else for that matter, including herself - but due to the fact that she is the main antagonist of the entire game.
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There are no "grey jedi" options and its possible the game designers did that on purpose. LS Jedi become super soldiers and DS Sith become roving magical cannons. Indeed, defying her teachings and going as extreme as possible rewards you by making you extremely OP. However, after the 5th or 6th play through you realize that there is no way to please her and that what she seeks isn't obtainable or even rewarded in the pursuit. On the first few play throughs, her teachings are profound because regardless of which extreme you take, she highlights all of the consequences of whatever path you follow. Either way, you are never perfect in her eyes. If you are more LS, she says you are not truly a Jedi and if you are more DS, not truly a Sith and she takes solace in that. The narrative of the game requires you to go to Malachore and face Kreia and defeat her and whether you are more Dark Side or Light Side, it doesnt matter.
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