Talent Gating now gone once you hit 25. Thank god, nothing like being a level 40 and having to deal with being handicapped because you are forbidden to pick the talents you want until you are level 4 with a hero. Thats a huge plus IMO. Also, ETC and Diablo just got a lot more interesting. Thinking about buying the Murloc skin for Diablo now too. Buying Kael bundle as well.
Concerning ETC changes, IMO you have two definitive builds you can go with. Self sustained healing Tank, or a CC/Damage amp tank. Definitely some interesting changes, but you will be punished harder for going YOLO unlike before with ETC. And with Diablo, you are going to see a lot of newbies using him and getting way out of position as a tank because "LOL I CANZ LEACH". Bad diablo tanks already had a bad habit of doing this, IMO going to be even worse.