Example, movement tag will limit how much damage it can do, knockback would most likely add the same including to the fact that it would start to not work after a few times because everyone in a fight with you are using abilities that have some sort of CC. Your ability damage is effected by the tags it has on it.
All CC starts to get resisted so fast because they couldn't figure out how to make it balanced. You probably wouldn't want that based on how they design ability rules in this game. After all his power is concussion blasts, some people and furniture and shit SHOULD go flying if hit He should have knockback on at least his AOE moves or something, one of the things I loved about his wide beam on X-Men Legends.fools would go FLYING.