I saw the opposite thread to this and found myself much more curious about what features you expected to suck and have ended up enjoying more.
For me; I was expecting the same old from Raids and found myself really happy with how they turned out. I was worried with DS that Blizzard had really lost their spark. I was also expecting Challenge Modes to be underwhelming and something I could AoE Roflstomp through and they're really not.
I wasn't sure if Blizzard could release a nicely balanced class after DKs... Monks really are pretty well balanced with no dire complaints. Warriors and Hunters are a bit silly in PvP but I was expecting the general balance to be much, much more gimped than it currently is across the board.
I didn't think dailys would be a good feature and I understand a lot of people are forcing themselves to do 30+ dailys, daily so haven't been enjoying them; I never enjoyed them in the past but I love having a solo time sink. These dailys are actually pretty varied and fun. I only do Klaxxi or Golden Lotus or Tillers on a given day and that's fine. I still get Valor, I still unlock rep vendors before I have the Valor to spend on it.
And finally, I was really surpried by how nice the continent and world content has been. The zones are all good. Story, good. Music, good. Questlines, good. Exploration stuff like Scrolls of Lore, good. Rewards for exploring, good. Rare Champion mobs, very good. It's all nicely proportioned, I find myself exploring a lot. They wanted to get us out into the world this expac and I am finding myself out there with a deserted capital.
So far I'm really enjoying this one a lot more than expected. I'm glad I came back.