I think the limit to no more than 8 is a bit excessive then people would likely just switch to playing aero (another already strong card) , Captain marvel which can be pretty effective or even Vision might see a boost in play then. However that could also lead to some other unique combos to get similar results such as venom or a few other reveal cards which could be fun but don't solve the doubling problem.

I think a middle ground of double power with a maximum of adding 10. So magneto still goes to 22, shehulk to 20 but redskull gets capped to 25. Which is still a strong play but manageable considering his special means average of plus 20 in lane.