Here's just one take on a system I believe would work for me. Apologies if the same suggestion has been made before.

Firstly, I think the selection of currently equipped actions needs to be decoupled from the setting of assignment to Action Bars. I would like this to be done through some kind of profile, that allowed different configurations to be selected from.

This would be an entirely new page, although the left hand column would be somewhat similar to the current right hand column when defining your equipped abilities at present.

Here is a very rough mockup of an interface.

http://imageshack.us/photo/my-images...nprofiles.png/

So the idea is that you make selections from the left and then add them to the current profile which is shown on the right. Once an ability is in your current profile it can be used regardless of whether or not it's in the action bar.

Next comes the action bar. The action bar settings would be linked to profile (not to current class), so when you first define a new profile it would be empty, but once you populate it you would get the same action bar settings whenever you set that profile. The action bar page would operate in similar way as currently, except obviously there would be no need to select from the class drop down when browsing for abilities, and the list on the right would only include things in your current profile. There would also be some new area where you can drag any of your defined macros onto the action bar (and possibly edit macros directly from the page. But I'd like macros to come from a global "pool", so a single macro can be used across multiple profiles).

The first row of the action bar would be accessible by pressing the buttons 0-9, as presently. The second row would be alt+number, and the 3rd ctrl+number.

Pro:

Easier to define multiple "builds" for different activities for any particular job.
Easier when selecting what should be equipped on action bar.
Able to assign macros to the "default" number keys.

Con:

Reduction in number of abilities that can be quickly access (this could be countered by adding "pages" when setting the action bar, with the up/down keys now changing the page).
More I haven't thought of.