not quite. iirc, single target healing gives 0.6 enmity per 1 hp healed, and double for every overhealed hp.
In the example given, overhealing 1.5k hp per gcd gives more hate than anything you could do to throw damage then heal the 2k hp lost in one heal.
There is a reason why the #1 method to get max reward on hunts is getting 8 stacked WHM to spam cure 3 :p
(also #1 method to reset mobs back when hunts were introduced)
I checked back and was going to edit anyway, but you're right on overhealing. For the heals themselves, it's not a flat out 0.5.
Cure and the HoT (regen and medica 2's HoT) are 0.5 enmity, but every other heal is 0.6 enmity for a WHM.
(if this is still up to date)
