I'm really liking almost all of the Theros cards spoiled so far. Toning down creature power is a good thing. Thragtusk, Huntmaster, and cards like them are just plain ridiculous. Bestow is pretty lame, but I love Hundred-Hands-Man, Daxos, and Artisan of Forms. Wingsteed Rider is probably going to be the nuts in limited.
Spell-wise, that 6cmc sorcery probably should have been 4cmc (or just Smite the Monstrous), but Curse of the Swine, Rescure from the Underworld, Read the Bones, Voyage's End, that RG Shock/Naturalize, and of course Thoughtseize are all really great, either in flavor or playability.
New Elspeth also makes me happy. She could maybe cost one less or have one more loyalty, but that's probably just my mono-white-walker bias talking - Elspeth and Gideon are my favourite walkers. New Elspeth seems better than New Gideon, and I loved playing with New Gideon, so that's good enough for me.