I don't see what the problem is with not being "skilled" at RP (enough to pull off a concept "well")? We're not writers. We're not writing a book. We're having fun. It's a hobby. If someone has fun playing a character who is that powerful, that influential, that special, why not? You're basically judging people for not having fun the same way you do. You don't have to like what they like, so judging them for not liking what you like is pretty hypocritical.
Edit: This is why I defend not RPing with people if you disagree with how they conduct their RP. You don't have to interact. This isn't a group with set rules that someone is breaking. Unless someone is outright trolling or otherwise trying to purposefully disrupt your RP, let them do whatever they want. Do your own thing. RP with like-minded people. Problem solved.
Edit: This is why I defend not RPing with people if you disagree with how they conduct their RP. You don't have to interact. This isn't a group with set rules that someone is breaking. Unless someone is outright trolling or otherwise trying to purposefully disrupt your RP, let them do whatever they want. Do your own thing. RP with like-minded people. Problem solved.