In our advocacy-focused implementation of Raiser's Edge, actions are important end products - not just a means to an end. Many times, we need to sort or filter a list of actions based on action attributes (custom fields). While it is possible to do this with Constituent lists, it is impossible to do so for Actions Lists.
I emphasize the usefulness this would give us! :)
This functionality would be really helpful.
And action custom fields should be usable in building dashboards!