After Wilder stops Breazeale and Kownacki this year to go 42-0-1 (41 KO), who will he fight in 2020? He'll be 34 years old this October
Looking at the WBC rankings... Whyte is ranked 1st but we all know that won't happen, Whyte would need to jump ship and sign with Haymon and I can't see that happening despite Whyte being less than happy with Matchroom at the moment. Fury is ranked 3rd and with the ESPN issue if he's not willing to go to DAZN for $100 mill he won't fight on ESPN who's offer was less than the DAZN deal. Ortiz is ranked 3rd so that's a possibility and If Ortiz/Joyce happens in 2019 and Joyce somehow wins then maybe Joyce could be an option. Breazeale is 4th and should of already been beaten by Wilder. Kownacki is 5th and again in this scenario Wilder has already fought him after Breazeale and won. Parker is 6th but is working with Top Rank and so again ESPN will be the main issue, though I doubt Parker has an exclusive deal with ESPN so not out of the question but highly unlikely. Povetkin is 7th and will be fighting Usyk and then likely retire and lets be honest no way they let him near Povetkin. Kabayel is 8th, possible but unlikely as it's not very marketable. Pulev is 9th but again with Top Rank and so ESPN issue again. Rivas is 10th, signed to Haymon, if he doesn't fight Fury then he could be a real possibility. Michael Hunter Jr is a Haymon fighter despite working with Matchroom so he could be an option if he keeps winning and can get ranked in the top 15, he's currently 20th. Charles Martin is another option he's ranked 13th and if he can get a couple of quick wins then might be an outside chance of fighting Wilder as he's also a Haymon fighter. So you're really looking at Ortiz, Joyce, Rivas, Hunter or Martin as the most likely if Fury and AJ doesn't happen.
I doubt it, he's far too easy to hit and couldn't even KO Martin. He's not awful but he's a level below guys like Whyte, Ortiz, Povetkin, let alone the top 3 guys. I think Joyce beats Kownacki right now.
Kownacki relentless pressure style would be too much for Wilder, I think he can't handle that pace, Martin as limited as he is, is a big guy much heavier than Wilder and a southpaw. Martin can punch and Kownacki took those punches well, so Wilder will have a tough time trying to hurt the pole, on the other hand, Kownacki couldn't bully Martin but Wilder is like 40lbs lighter, so he won't go toe to toe with him.