Yeah i have to agree on the whole clickin thing, im ashamed that i sometimes click a couple of my totems, but i can understand how in Naxx healin like that was fine, but to be honest Ulduar is bringin a level of difficulty beyond Sunwell imo, so those 0.5 secs your talkin about well thats actually alot and there are encounters which require us to heal in that time frame or the selected player will die and it will be our fault.
Jst get your spells together think of which you use the most and start keybinding !
1-5(6 if you got big hands or a small keyboard
), shift 1-5, r, f, v, shift rfv, etc. Those keybindins alone should give you enough for all important spells and are all very accessible and if you cant make those work then im very confused