I would like to "Turn off" some of my useless skills I don't need and only got for getting something better. (like getting gunnery only to get rouse, or kraken's coils only to get triton's song)
In the Powers Page I would like to double click a Power and turn it off, so it doesn't appear in my skills bar, and then double click it again to put it back in!
I agree with this (although I usually don't learn other spells) but if you want to reduce the chance of seeing those useless abilities, just open your powers page [P] and dragging the ability to the end. The lower the number, the higher chance you see it in battle instead of other spells.