That guy sounds like he was impossible to work with. Your characters can't all be ALL THAT and a bag of chips, you gotta have moderation. One cool character with solid skills, and then one who is working on it. But to have two sort of based on powerful types who want everything to be about them? I wouldn't put up with that for very long. The worst part is when those writers can't seriously see what's wrong with their ideas. I'd rather have someone outright admit to wanting to be overpowered or play a special role, than someone who thinks they're actually contributing.

Though I do gotta admit I have played 2 OCs who have been long lost daughters of a cool canon. My Naruto OC had her own blood targeting jutsu but her age and history backed it up, and the plot didn't revolve around her and her father reconnecting, but actually around other canons who she got to help, I didn't even want to ship her with anyone but my partner kept pushing his Naruto onto her so it happened lol

But those are instances where people are open about playing a weird OC or an OC for a certain canon still are easier to deal with since they're up front about what they want and why their character is a certain way. At least to me, I'd rather have someone admit they can change things, rather than be super stubborn and blind about their roles. A writer who can't step back and see issues is just as bad as someone in a bad relationship who just ignores red flags. I mean, when you're looking at something through rose colored glasses, red flags just end up looking like flags.