With lightning reflexes 8 agility gives slightly more damage than 24 AP in total where ZG enchant has 1% to hit and 10 stamina which is very nice for Naxx where +hit is needed. But in terms of pure dps, 1% haste seems better than all since after a while 8 agi or 24 AP don't increase your dps by 1%. So I'm thinking to actually remove my ZG enchants on my dps gear and put 1% haste.
I don't understand why you're so interested in such marginal improvements in dps (for you +8 agi is only a tiny bit worse than zg enchant) when you could make a much bigger improvment in dps by changing spec.
EDIT: And I wouldn't be putting on a haste enchant since that really only helps if you're just autoshotting... and I never just autoshot, even as a horde hunter, on any fight where dps matters.
Even with your non-ideal raiding build, that makes the 8 agilty into 10 agilty (20 RAP around .4 to crit). If you aren't at the 8.6% hit cap, then ZG is clearly better, past the hit cap agility may be better, but you are forgetting that you can never go wrong with more stamina.