If you would prefer me to use: This character is overpowered relative to the other characters I can use that term.
I would actually. It’s a more specific statement that cuts through the bullshit, making it easier to tell you you’re wrong without having to also discuss a whole other topic on top of it.
Not to mention, if we’re talking about sexists or subconscious sexists, it’s a gendered insult (forget the male version which no one ever brings up except in a debate about the term). Again, whether conscious or not, the more you use the term the more some people will simply associate it with “powerful female character” rather than “too powerful female character” and end up writing off the former just because (while the powerful male character gets a pass for a number of reasons, conscious or not, sexist or not, including simply that they are more common and don’t have a term as closely linked to them that will trigger such a response).