Seems you’re pulling data for all ranks. For top 1000 Legend (edit: past 3 days), the story is quite a bit different. I mean, Priest still last, but the winrate gap is smaller.
- Hunter, 53.1% winrate, 12.4% popularity
- Rogue, 52.2%, 17.9%
- Druid, 50.0%, 19.7%
- Warrior, 49.8%, 14.3%
- Mage, 49.6%, 6.9%
- Warlock, 49.2%, 9.5%
- Demon Hunter, 47.9%, 5.7%*
- Paladin, 46.5%, 5.9%
- Shaman, 45.6%, 6.1%
- Priest, 44.2%, 1.5%
Edit: * the top performing archetype in this meta right now is actually Fel Demon Hunter, but it’s not popular at all; most DHs are Quest Lifesteal and there’s way too much experimentation with sub-40% Proving Grounds decks.