I don't know where to put this, so I'll post it here for now. Starting around Veteran rank 3 and higher, I find myself swapping in and out abilities just for trash mob fights, I've had some really nasty ones that have 2-3 casters or a lot of hard hitting melee from one group of trash to the next. It's time consuming having to open my skill window to swap one ability out for another then swap it back when I get to the next group.
My suggestion is allow us to add up to 3 abilities per slot like a dropdown menu or in this case, pulls up, only 1 ability can be active and can only be swapped out of combat. It works much like quickslot consumables, but instead of pots and food its for your skills and ultimate. People are going to suggest I put my alternate skills in the Weapon Swap, well I have my healing build there as do many others tend to go that route the further you progress even then I like to swap out some of my healing spells for different fights as well also. This lets you do it faster, like if your group pulls while you're in the skill window swapping out, they may have already pulled locking you out in the middle of changing.