Yesterday I'd say Povetkin, but Wilder proved he's very effective in long distance, can take a punch and withstand 12 rounds. So I'm not sure. It might come down to scorecards again in which case Wilder would mostly likely win by UD.
Povetkin is better than Stiverne in every category, with just as good of a chin and power. Povetkin by stoppage.
I'd still favour Povetkin. He'd apply a lot more pressure and try and get inside and would work the body. But Wilder is dangerous, he has the size and reach and could hurt Povetkin on the way in.
Will still take Povetkin at this point as he has proven his caliber more consistently at world level. Pov would apply better, more effective pressure than stiverne for sure and wilder isn't physically strong enough to manhandle him in the clinch. Think Pov wears him down late but a decision win or knockout is by no means out of the question if wilder keeps distance
Povetkin's timing, tactical and strategic ability are far greater than Stivernes. A win would go a long way in legitimizing Wilder as a truly worthy challenger. However, one thing Povetkin does consistently: Win