It's literally there. Rework of an existing character involves an existing character. Suggesting a new character does not involve an existing character. Isn't that simple?
There is a bias towards existing characters. And no one cares about new made-up characters
Welp, and plutonica looks like a walking demon core/atomic bomb. The fact that she effortlessly carries around this massive shell conveys her extraordinary power. Also you pretty much can't confuse her with anyone else in the cast, or with any other object in the game.
Also massive hitbox may...
i'm gonna use chunky McGinnis as an excuse. Both have periodic spirit damage (radiation and mini-turrets), both have some from of lockdown (proton flux and wall), both have sustain (med specter and fission field), and both have a spirit nuke ult. And also both have a nice gun potential with...