Nerf down. I feel like I would enjoy much more playing a game full of Grodds rather than a game full of Catwomans.
I tend to play characters that have to work to cover their weaknesses more than they have to worry about oppressing the opponent, and that's where I find the most fun.
Imho all characters should have a lot of holes. It forces the player behind them to play smart and think more about what they are doing. I see a lot of characters in this game that I think seem to be perfectly balanced, able to compete, have a lot of potential, but at the same time have major weaknesses, as all should. Kung Lao, Kano, Skarlet, Jade, Noob Saibot, are examples of characters that I think would be perfect if not for the likes of Erron Black, Geras, Scorpion, Sub, Sonya, Liu Kang being so dominant and complete to the point of making the good-but-not-dumb-characters not worth the trouble.
I particularly hate the idea that all characters in a fighting game should be complete. They shouldn't. It is fair for a dominant zoner to lack great close range moves, it is fair for a heavy rushdown character to do struggle to get in, it is fair for a 50/50 character to do very low dmg, it is fair for a grappler to be slower, etc...
Characters should have downsides, and they should define them more them they strengths do imo. If you balance a game around the ways you can counterplay every character you may end up with one or two shitters but the upper echelon will be much more packed together than when you balance a game around the ways every character can put their shit up on your face for you to deal with and end up with a lot of shitters and Kabals, Cyrax, Zod...