To start, it's going to be hard to really judge balance because it was kind of hard for me(and probably others) to play on the Blizzard settings which you couldn't change, (no autohealth bars or custom hotkeys) and basically if you played pretty standard you owned people who were messing around with the new units.
Mothership is so good, I think there should be a pretty decent nexus first build vs t/z where you don't even need a forge depending on how much energy it starts with. The range on the mothership cannon is really crazy but it's not as useful late game, so it seems like early game rushes vs protoss are majorly nerfed now if not completely eliminated. If the starting energy on the mothership is nerfed it would be a pretty big change for possible early expand builds. I never played a mirror in Hots but I'm also guessing that earlier expo's will be better in PVP which I think is good/more interesting.
I think the energize skill is going to be the most usefull skill, people were talking about energizing a nexus to max your chronoboost but I was energizing my first oracle for full mana and starting out with 2 entombs which is really strong early game. I also realized there could probably be a build where you just get out an oracle, energize it, then you have your entire army cloaked really quickly. Also energize will be really useful if you want to warp in a few templars and actually have energy in an emergency or even full charge a sentry so you can warp in different units instead and have plenty of force fields to hold your ramp. Your unit just has to be close to your nexus/mothership for it to be in range but there are so many good uses to energize as a lot of protoss units need energy.
As for the mass recall skill, I think it's pretty balanced because it costs a lot of energy so you aren't going to be using it so early and has a much smaller aoe then the current one so it's probably best used for late game harassment or to like save the last 6-8 units u have left if u are losing a fight. Depending on how it goes there might be some really strong blink stalker with recall builds.
Oracle is a really good/cool unit, can harass, has emergency detection, which in some ways can be better than an observer, and the cloaking is really great. I think the aoe on entomb might have to be reduced a bit; it seems like a full entomb on 2 bases can really set your opponent back. The cloak ability should probably have to be researchable on the cyber core like hallucinate to prevent really early game cloak abuse, but even with some nerfs I think this will be a good unit.
As for the tempest, basically it adds really nicely to the protoss deathball. In some ways the colossus/ tempest combo could be stronger than colo/templar, but in some situations maybe worse, so I think it's cool. The range upgrade is kind of unnecesarry and silly looking. At one point I was trying to harass a mineral line with them but I realized it wasn't working out too well because their range is way further then the vision and then the queens were killing them when I moved them closer. They are a really slow attacking units so they are pretty bad vs fast attacking units but they work really nicely vs corrupters/vikings. They were originally advertised as a counter to mutalisk but I think they will work vs mutalisk almost the same way that thors work vs muta, which is depending on your positioning/unit count.
I think the main strong point of tempest in PVT is vs mech, they are bad vs marines but really good vs all of the mech units. It seems that tempest are also good at defending harass drops because they just shoot all the way across your base and your opponent has no idea where you are shooting from, I'm just not sure the resources required for tempest are worth it for defending harass until really late game. I think i would rather see the tempest have energy/some sort of situational spell like tower disruption or something instead of range, it also might be a bit less silly/require skill if you could feedback them in pvp.
To me it seems like Protoss in hots is the most complete race, like how Terran seems like the most complete race in WoL
I'm really bad at T/Z and I barely played them so I'll just say a few things.
I'm not really sure if the mines are actually good or really terrible. They are really easy to micro against, I'm usually leading with zealots and if you just micro them they aren't really cost effective(100 mineral vs 75 min 25 gas). Mine drops were kind of really bad as long as you pay attention. It seems like mines are going to be really good vs mutalisk, and other air based harass and the mines killing cloaked units is kind of weird. I think people will eventually start putting mines in random places/rely on the luck factor a lot.
On a side note, I think the lore part of the mines is kind of dumb, I mean I think all of the other terran units are controlled by actual people. Here you just train the mine and the mine has can just walk around and do it's own thing. It would probably make more sense if an actual unit dropped a mine, and why would a mine add to your supply count?
Battle hellion- kind of seems like a nerf that they come out in battle mode as you're always going to want them to start out in regular hellion mode. It seems like the battlemode will only kind of help vs zerglings/zealots in a defensive way, which I don't think they actually need.
There was basically a mech version of a maurader which I either heard both was bad or was really good. I never played against one, but I did see my diamond friend playing off race protoss and totally wreck a master terran mech player with tempest, but he complained about them in ZVT
It pretty much seems like the infestor/viper/swarm host are all variations of the same unit. The viper pull is almost like a neural parasite, while the swarm from the swarm host are kind of like infested terrans. It was surprising that the swarm host units could attack air but it seems like they suck anyways. Mines will kill burrowed swarm host(I think), also when the swarm spawn out of in range of tanks the aoe also kills the burrowed host. If you could burrow and charge up like 5 charges of swarm guys and then release them all at once the swarm host might actually be good.
The Viper had hard time doing anything vs my cloak, and if they hit an oracle, usually it's fast enough to move back in time or I just have at least 2-3 of them anyways. Viper might be better once people actually know the hotkeys/are playing on their own setup. So far it seems like the best part of zerg is the upgrades to hydra/ultra and as Protoss I don't really fear the viper/swarm host as much as I do the infestor.
As far as general trends, it seems like detection is going to be a lot more important, and mutalisks are going to be less effective and protoss fast expos are going to be better.