Reading all the posts on the Hyjal wave pick-ups, it really surprises me more people don't do AS+Holy Wrath. My last Hyjal clear showed Holy Wrath as doing 8% of my dps (thus, over 8% of my threat) over the whole night. Given it's cast once, right at the start of each wave, that's a nice big chunk of front-loaded threat, and a highly visible spell cast, letting dps start to unload sooner.
WWS link:
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Not saying that's the "right" way to do it, but it certainly works for me.