Despite my ranting I do give Blizzard a bit of sympathy. They experimented with StarCraft: Ghost, and it failed miserably due to whatever reasons. Blizzard is probably particularly gun-shy about trying anything new with the StarCraft line, and wants to get a new StarCraft out that is guaranteed to sell.
The new units from what I can gather with the Protoss are pretty simple;
Zealot
Immortal - Replaces the Dragoon (essentially a Battle Droid from Star Wars Episodes 1-3)
Stalker - Dark Templar version of Dragoon, has the Blink ability (from Warcraft 3: The Frozen Throne, same name and usage)
Phase Prism = Edit: After re-reading the description, these are actually quite interesting. They don't just replace the Shuttle from Starcraft (by acting as the "exit" to one of those Zerg Nydus Canals), and the Observer, but they are also a mobile Pylon building (Terran technology, Zerg "Overlord").. Oh wait, that's just another cop-out.
There are also the tall "Tripod"(read: War of the Worlds) units in the Gameplay video that look particularly adept at taking out buildings and large groups of ground forces (i.e. zerglings)
There is something like the Scout, except it has the ability to shoot lots of missiles at air units.. Why this ability is Activated and not just a static method of firing is beyond me.
And of course, the Mothership. Which looks to be the new Carrier, except retardedly overpowered. It can shield itself for a limited amount of time, making it indestructible. It can also fire lasers at the ground which devastate any ground units and buildings almost instantly. And it can create a black hole which sucks in units(air only?) killing them instantly. All the while with an attack that is identical to the above unit (the Scout-type anti-air) except it can also hit ground units with the missiles.
All I've seen for Zerg is Zerglings and Mutalisks. Terran all I've seen are Ghosts, Carriers, Marines, Wraiths, and the 'Jump-Pack' Marines (read: Warhammer 40k) that seem to be oblivious to terrain levels.
They are welcome to make any claim that this is new but paralleling it to Starcraft 1, other Blizzard games, and external science fiction worlds, it's pretty plain to the eye that it is a compilation of rehashed ideas with the Starcraft named tagged to it.
If you are going to use a name to sell a product, be adventurous with it. They could have made it a dating simulator and it would still sell if it had Starcraft on the box.