Certainly, it all depends on the group, and the GM. If you use the alignment system SOME, you can get away with stuff like that, but in my experiences, and I haven't even run most of them, the GM holds the Paladin in a special place of forced actions, where he COULDN'T allow your CE Psion; not stopping evil is as bad as helping it, and the Paladin is basically an accomplice. He'd HAVE to root out evil, and try to purge it. If he didn't constantly try to persuade the Psion that his is the wrong path, he should lose his god-granted powers.
I certainly won't tell you how to run your games, but I will admit that, to some extent, we will see how certain characters might, or should be conducted as differently. For me, Paladins must enforce their narrow view of LG on everyone around them, because it is the core of their class aspect; they are holy warriors tasked by the Gods of Good (usually, I mean Correllon has pallies, and he isn't LG, for instance) to snuff out evil, and protect the weak from the mighty, especially who are also evil. Thieves are not always picking pockets, nixing things, and being obvious about it, certainly, but a Paladin who is not in a video game where you NEED that one key, to open that one door, and the guy doesn't want to share, so you NEED to steal it is likely to look at the act of theft as wrong, rather than justify it with why, and begin the slippery slope of gray area that he will lose his powers by falling through. My opinion, of course. My other opinion is that I never really liked the Alignment system, in D&D or most games, and if you don't focus too much on it, I can see more of what you said working. I'm just a bit of a stickler, sort of like how you probably won't convince the Druid that burning down the forest is the best course, even if it somehow is. New life will grow there, and a stray bolt of actual lightning COULD do the same thing, and the Druid might not flip his crap, and desperately try to stop the raging conflagration, but when civilization's hand, or something similar, decided it, he's likely to *****. And, I'm done babbling now.
And this has not a lot to do with the OP, so sorry I sort of derailed it all ![]()