Oni
First Post
IMHO if a players says to you I picked power x last time we leveled and after a few sessions I think it stinks or i think power Y would better fit our party or my character concept how hard is it to say go ahead and change it? Do we really need a rule for this? I would further add that if someone is playing a class they figure out isn't fun for them you write that character out and write in the new one when situation best allows for it, I don't see the big deal.
Or, heck if they really like the narrative of their character, but not the mechanics of their class I have zero issue engineering a situation to fix that, or doing a little retconning so they can enjoy themselves properly. This is supposed to be a fun activity after all.