Considering many top rated arena players swapped from Alliance to Horde when Faction changes came out, something needed to be done with WotF, but not this, and not this way.
In the lower brackets, WotF probably isn't the top racial in the game, but as the brackets continue up, I believe it becomes far more gamebreaking. If you can break fear without your trinket, then you save your trinket for something like blind/deathcoil, etc.
Gift of the Naruu does squat at 80, Every Man for Himself is "ok", depending on your class. It's nice to free up a trinket slot, but the WG trinkets and the new and improved trinkets have stats that are to be desired for pvp players. Shadowmeld is nice for tricks and giggles, but it's only decent at lower brackets and does less and less as the brackets progress upwards.
A lot of ret paladins went horde to grab Arcane Torrent for another interrupt (as far as I know).
And then Will of the Forsaken... If you pitted a Horde UD PMR against an Alliance PMR (both standard mut rogue, disc priest, frost mage), equal skill, and RNG forgiving, Horde should take that matchup, no question. That's a racial swinging the balance there. Sure it's just one example, but still, it's an example.
So I guess TLDR after that rant.... WotF needed a nerf, but not to that extent and not at the same time as Race Changes because that just makes Blizzard look like dickwads. There needs to be some level of rebuffing in my opinion, but I don't think it should be giving it a base resist of 15%. Remember UD also have a resist to shadow spells already, and adding that on would give Fear around a 17% resist rate. Good luck fearing an UD warrior with that.