My main problem with the Warhound is that it is expensive and uninteresting, as others have pointed out. As well, protoss now have 3 casters, zerg has 3 casters, and terrans still duel with their two unchanged casters. You can clearly see how Terrans look uninteresting and lacking if you see the latest multiplayer unit video. The Widow Mine is great, but the rest of the new stuff for Terran isn't that great.
Dustin Browder mentioned they had to cut zerg stuff out of the demo because of several reasons. While they seem to know what to do with Protoss and Zerg, Blizzard seems to have reached a new block regarding new Terran units. It's like the Thor/Maraunder/Siege Tank issue all over again.