Minmaxing is impossible, yes, but smuggling in OP character is.
Sure but, even so, the point of the RP is not to have the most powerful character, and people should absolutely not be using their power to bully other
players into doing what they want (bullying characters is, of course, OK, but not if it's going to wreck the RP for the person playing them, or if they have a good reason not to want to go down the path you're trying to force them down).