Yeah, but... I mean, I expected that thing you was doing before, with a detailed explanation about the unit and what it does and where it is on the techtree etc...
I still haven't got around to making the Haunted Boneyards one yet, because it isn't a media update. A media update just showcases new imagery, soundtracks, etc. It doesn't reveal much information.
But... The buildings have a lot of light blue and gold, that's more like a Protoss theme rather than a scary Undead theme imo.

Plus, the units' eyes will glow light blue. Opportunity to make hollowed\rotting\dead\empty eyes or red, creepy glow(see: Dreadlord) ruined.
Like I said, wait until you see it in-game. There will be a lot of effects and animations that will contribute to the creepy theme. The coloured concepts are just that: coloured concepts. They don't resemble the real technique at which the buildings will be textured in-game.
Also, I was sincerely expecting the Undead music to be something like the WC3 "Defeat" music for the Undead or the current SC2 Zerg tracks. Like, creepy. Kind of like the "idle" theme, but the Defeat and Battle musics just don't kind of fit.
We didn't feel the music was that great in Warcraft 3. Yes, it had a lot higher quality than our compositions but it felt too much like an ambient piece rather than music. Thus we aimed for a much different approach that should make you feel much more inclined to listen to the music rather than turn it off.
No, I mean. The battle track for example. When the battle begins, it starts. But what if the battle ends while the track is halfway through? There should be a smooth "volume down" for that track, after which the other track slowly comes in and builds up volume.
What you quoted is the answer you are looking for: in each track there will be specific "points" on the track where we've made transitions. For example, every 10 seconds there will be a transition point where there is a transition track made specifically to end that point off. It's harder to explain in words than to think of
I'm glad you are looking forward to the release.
Anyway nice concepts, though I would actually expect from you to use nerubian architecture for all undead buildings.
The Nerubians aren't in control of the Scourge, they are only a part of it. Since the Lich King is the leader, it only makes sense to make his buildings represent his own theme.
Cyan burning eyes are kinda strange, a weak cyan glow inside would be perfect, symbolizing that each soul is controlled by the Lich King.
Only Tier 3 units will have the really large glowing flames for eyes. However, Tier 1 and 2 units will have the cyan glow you described.