I wasn't particaularly thrilled with HotS either. :D About the only thing that was good there IMO is the awesomeness of the fact that we get to see Zerus... but that was not what I expected.
They are great craftsman without doubt and visual quality-wise their animations are excellent. But I feel alienated by many decisions since WoL, and I assume I'm not the only fan who is.
To the point where I actually lost hope. :( I watched the trailer out of curiosity, not hype, and I'm not going to buy the expansion methinks... This time I'll wait.