I'd say Cataclysm questing and zones were a lot more interesting and breath-taking than MoP. The quests had major relevance to the overall storyline since vanilla WoW.
Temple of Kotmogu though is amazing. Cata bgs sucked compared to just that one and I haven't even stepped foot in silvershard mine yet. Dailies I'm meh about. Obviously none of the MoP dailies are at the level of the Molten Front but that's to be expected. I just need to get into the grind mindset. The rewards the new dailies offer are unmatched by anything seen in this game before.
PvP balance overall seems a lot better than at the start of any other expansion despite the lack of MMR reset. Tweaking is still needed here and there for things like healing and fire/frost mage and warrior burst.
The dungeons are...interesting to say the least. They're definitely nothing comparable to the tBC dungeons or even WotLK dungeons. Maybe not even the Cataclysm dungeons. But then there's scenarios that I prefer doing anyways so that's great. I'll get around to challenge modes eventually when I at least surpass the ilvl that you're balanced to.
Haven't touched pet battles yet.
Lorewise the game is new and completely irrelevant so far to the Warcraft story which is a huge turn off.
PvP-wise it's looking pretty good but nothing to write home about.
In all honesty I can't say this is any better than the start of Cataclysm at all (which was great mind you). The coming weeks with new raids may change my mind.
It all comes down to if the expansion will have true staying power in the long run which is where Cataclysm was horrible.
I do think though that since they've been attempting to add a "gating" feel to the game again that they'd might as well just flat out add attunements quests back in. Hell, attunement dungeons would be fine too just because LFD is in the game.