well i am clicker, so what i do is using the mouse buttons. I am playing with a naga razor that comes with 12 buttons. Add mouse wheel up, mouse wheel down and pushing down the wheel kinda gives me the possibility to use 15 at least abilities without taking my eyes away from the action.
to be honest, practically i use 6 buttons (from the 12 buttons) and i use 3 abilities with the mouse wheel (wheel up, wheel down, pushing down the wheel). but those are the abilities i usually use. The others, are in the bars, i just click them when needed.
As for the cooldowns, now that they added the cooldown in seconds, its far more easier (imo).