I think they should have every ability save to the type of weapon. If I pick up a sword, all my abilites I last used would be automatically set to my action bar.
It would also be beneficial if they let us save a couple sets of actions that would could choose from.
I have a few sets: Solo, tank, DD, support.
Why not give us an easier way to change between these.
In reality, within each class if this was done, I could call my tank set-up (as a GLA), Paladin, or my DD Warrior. This is a way we could keep the traditional classes alive without scrapping our customizability.