Tempests are amazing. Holy crap, if you get enough of them up, they have unlimited utility and the enemy can never attack into you (and I've been saying this all along rather than focusing on crap like DPS). In PvP, I've been starting out with some sort of Immortal expand (although I don't like it very much.. might go like 2gate Phoenix expand), and then getting Tempests on 2 bases. All you have to do is stay active with the Tempests and the Mothership Core for recall, so you can pick at his army, economy, etc. If you have enough Immortals, you make it totally impossible for him to attack into you with a lot of Stalkers (around 4-6 Immortals along with Zealots and Guardian Shield is super strong). In PvZ (and PvT if you can ever manage to get them up without dying), support with Storms and they can never launch an attack on wherever your Tempests are unless they have some really good Viking or Corrupter spreading (and have tons of them). Tempests are so good, I honestly don't have reasonable intentions of making Carriers anymore.
Free Hallucination! Great scouting tool. The fact that it required research all this time was kinda BS. Now if a Terran takes gas, you don't have to get a Robo to figure out what is going on behind his wall... THANK !@#$ING GOD.
The full-sized Mothership is worthless as hell now. Vortex does absolutely nothing.. Mass Recall is only useful if you derped your army really hard (not to mention it recalls back to a Nexus instead of everything to the Mothership). The only time I see it being worthwhile is in PvZ if you want to cloak a 3rd base and then snipe Overseers. I guess it could be good against Swarm Hosts?
I haven't made a single Colossus yet, and it's been awesome.
Oracles are decent, but they kinda lose to any sort of static defenses. Haven't experimented much with the time warp thing, but I'm sure it's really strong.
I think DTs are the most rare unit in the game right now, hence the low gas cost for the Dark Shrine. Almost everybody gets blind static defenses to prepare for Oracle harassment, so DTs will never do anything. Maybe in PvT, DT drops can still be strong, but it will definitely get blind countered a lot more often.
PvP is a pretty good matchup now. Lots of interesting openings and far less blind-counter wins with the Mothership Core on the field. Macro PvP is actually fun now, because Colossus builds die hardcore to Tempest builds.
Overall, the game really plays into Skytoss, Storm and harassment stuff.. things I always wished were stronger in WoL. HoTS is gonna be sick! So much less a-moving, longer battles, more harassment, and less blind-countering/guesswork. I'm excited.