Freeze mage ? what are you people on lol, freeze would never run this if it had even better stats. Might see play in Hunter for sure, would have certainly seen play if it had the beast tag. I think it's pretty good.
Because it's considered a statue, like Spectral Spider isn't considered a Beast because it's a ghost. Although, they have screwed up Beast synergy in the past, like when Silithid Swarmer wasn't made a Beast until recently.
Great for Pally and mage. Mage has IceBlock that will stay forever and pally even better- Secret Trial, not easy to proc, costs only 1 mana. So this becomes 6 mana 4\7 taunt. Not sure about hunter, all traps there are easy to proc but with that 3\4 guy making secrets 0 mana having 3 of 4 secrets that should be no problem.
The only question is, can it stop aggro or is it too slow at 5 mana?
The current midrange hunter deck has a lack of five drops to run (Stampeding Kodo and Stranglethorn Tiger have mainly been teched in for beast synergy). If Secrets are added back into Hunter due to Cloaked Huntress I can see this being played since it's (potentially) one attack away from a Houndmaster buffed Tiger on turn 5. Sure it lacks Beast synergy for Kill Command, but a 4-7 Taunt is very impressive