Everything that needs to be said has already been said, but all I can say is; Hardiness is just really, really strong. I have always thought it was strong, even when I played Vanilla back in all those days. People always praised Will of the Forsaken (which is also good) but Hardiness overshadows it in my opinion.
This trend continues on private and will likely spill over into Classic with amount of ill informed players... The more players who use WoTF though will indirectly buff hardiness so I am totally okay with this.