i dont doubt there are different 'attitudes' of healing
imho the 'keep them' high is the better one because
1. if you let them drow until it is worth healing, well, maybe you mess smth up, or the to-be-healed does, maybe suddenly all the mobs focus on him -> dead, only because you waited ^^
died even though you could have saved him, well, thats not that good i guess :P
2. morals of the person, as mentioned above
3. morals of the group.
well, assuming you are a 'i'm teh uber 1337 h4xx'-player, liking to quit very fast and so on.
where would you quit sooner, in a group whose health is always near full, or in a group that is sorta always on the egde of extinction ?
no matter if some players should leave then or not cause they are supposed to be leavers/jerks/whatevers anyway .. as long as they dont pull additional mobs, they are just additional firepower, which is always good to have around.
5. woh is only 5 energy, smth you'd easily regen again. heal other would be another matter, save that for more dangerous situations, but still, try to keep ppl up with low recharge/low cost spells ( you heal through divine favor too, after all ) like dwaynas kiss, woh and so on.
in the end, there is no 'perfect' healing or monking method. every monk has his own, but thats the one i use and find best, cause it is not so fixed on the condition of a red health bar, but is also taking the mentality of the player behind the war/mes/whatever into account