aye that would have worked, that way it wouldn't need to be spec specific, if you're ret it copies your attacks, if you're Holy it copies your heals, the problem would be prot, you could do something like make it increase your Block by x% for the duration, that was Ret wouldn't gain an extra benefit, as they don't have a shield equiped, and Holy wouldn't gain any as they're nowhere near the danger anyway.
also giefv Glyph of GAnK to increase threat by 50% while it's up, similar to DRW's