I'll start by saying the forums for this game is a bit different than other games and MMOs I've played. It's taking some getting used to to navigate it. I didn't want to make another thread on a topic that may have been talked to death so I did do a search for my suggestion input, but I didn't see anything that matched.
I am unsure exactly why this game chose the 5 skills for combat at a time, my personal guess is to make it the same as what the console players will have, or to keep it more strategy based by making you choose. I'm sure someone will correct me.
However, I'd like to see toggle skills taken off the skill bar. My Nightblade uses Siphoning Strikes. It's a skill you click on and then let it be. It sits in the #5 slot on my bar during my PvE. Perhaps having toggled skills in a seperate window to be turned on and off before you enter combat, while letting you keep attack type skills that require use in your five slots can still keep the game as intended, without seeming like you're wasting a slot.
Just a suggestion!