AFAIK this isn't a repost. Me and my friend were questing in Dragonblight and I gave him water walking while we was fighting a mob and it instantly began to come after me, which means Water Walking is working as a taunt for some reason now. All I do is target the mob, then target my friend and cast water walking and the mob instantly begins to move towards me, having full threat.
video proof (sorry for short video, had to make it short so it would upload quickly)
Edit: I just tried it on a tank about 50% of the way through Anomalus' HP and it didn't work. I think the amount of threat it generates is just abnormally high, though not high enough to counter a prot paladin apparently.
edit2: Using it further in the Nexus, I've realized that it lowers the threat of the person who is targetted by it, not raising your own.