This is a huge misconception. You have to have really good reactions/spacing to win his bad match ups against top players. The biggest reason why I lost to Honeybee at UFGT was that I didn't punish his dashes as much as I should have, so I got run over. You have to know almost every string in the game to play Doomsday effectively, and what the frame data is on those strings so you know when your opponent can be interrupted. He takes a lot of time to learn at the highest level. I don't even know all the match ups in this game. I don't have a good Zatanna/Bane/Sinestro/Zod in my offline scene. Like I said though, totally doable, I just don't think it's worth it.
Eventually everyone will know the match up as well as SoCal and Florida. When that day comes, I'm scared for Doomsday players. I'd bet a lot of money on Theo/Gross against a Doomsday in tournament. It's just an opinion though. No need to get crazy.