It's Riot's consistent problem.
They rework a champion and make it top tier so that it's popular, then claim the rework was loved by players because the champion is popular.
I don't mean any disrespect to Warwick's rework - I think it was a good one. However I don't believe he'd be nearly as popular if he were weaker.
Riot seems to believe that reworked champions are super healthy and thus are allowed to have high win rates without being OP. As you said, the kit can be healthy with the numbers being too strong. For me personally, Warwick seems too strong in full health 1v1s when he's built to chase down and finish low health enemies. He shouldn't have high numbers for early 1v1s when he already gets to guaranteed catch and kill anyone that gets low on health...
So either that, or Rioters get a big bonus if a champion is super popular for a while after a rework and we just have to wait until the bonus is paid for them to be willing to nerf him...