Like weapon sets, there should be one slot that lets you define a full suit of accessories (not armor, since that has the equip timer) that you can (re)equip with one stroke.
Obviously, the point of this is to be able to use clickies of all types and then switch back to your actual usable accessories with one button. This wouldnt let you do anything you dont currently have the ability to do - it just saves you from having to assign several hotkey slots to your combat-use accessories, individually...it would just let you equip your entire combat set simultaneously, so whatever clickies you have equipped get replaced. It would just save room on already-crowded hotbars.
Alternatively, let us click clickies (except weapons and armor) from our inventory without equipping, but I can understand that might be harder to code...or convert clicky equippables to non-equippable inventory clickies (say, for 1000 Siberys and Khyber Dragonshards each, or something). Rechargeable potions, essentially.
Additionally, I'd love a way to add to the max charges on a clicky...maybe combining a bound clicky with an unbound clicky of the same spell, same CL, plus some additional mats, would add one additional charge to the clicky.
Again, it doesnt do anything but save you inventory space full of redundant clickies, and it gives some value to things like Divine Power clickies, which would always be in demand for adding more charges onto people's items, and gives new/lower level toons something useful to sell when they find them. Everbright would have to be excepted, since that's craftable.