Gotta be AonDor from Sel. I loved the concept of Allomancy in Mistborn but the fact that it is hereditary and the fact that Mistborn gets a huge advantage above regular mistings make me dislike it a bit. AonDor is random, which I love, but is also based on persistent and constant practice and study of Aons. I like that a person has to study to learn how to use a power, which is quite unique, rather than just been given a power on a platter.
Well, I guess we ARE getting into this. My point still stands despite her not creating the Radiant persona yet. She shows visible discomfort at wielding Patternblade (earlier in WoR) against Tyn. But with Kaladin, she does so without any hesitation. Later, when Adolin wants her to use it, she's forced to create the persona because she didn't want Adolin to see the real her. If she felt that way with Kaladin, then she would've created that persona in the chasms itself.
Well to be fair, he said he wishes he could do the same, and that whatever she's doing, it's working. He says this from his point to view, wishing he could move on from his pain, though, obviously, she took it in the wrong light. I'm not saying it's her fault, but it's not totally his either.