The counter to this argument is if you can't heal through big pulls then I won't do it. I normally do big pulls, BL hard for example only needs 4 mob pulls to do the entire dungeon (not including boss). But I've been in instances where I do my normal thing and pull big and suddenly I find myself burning through my cool downs too quickly because:

a) the healer can't keep up
b) the dps are too slow
c) a and b

Keeping hate is not that hard. For wars its flash, OP, SC and for pld it flash and RoH, though I find holding hate as pld in large pulls (6+ mobs) to be a little harder since they lack the aoe enmity that wars have.

TS;DR Yea I agree with the op.