This is a good idea and a lot of players would find it useful. But the downside is that unless a spell (Ascension or otherwise) is on a "real" hotbar there won't be any recast feedback, i.e. numbers or windowshade tint. A simple countdown timer can be put on each icon to simulate real feedback, although when Spell A resets the timer on Spell B, it wouldn't be acknowledged.
In both of your PM's there is a prototype window with icons that auto-switch for your Ascension class. Give it a try if you have a chance and offer your comments, either here or there.