So first on my list was that I really liked how AE had you "ready" spells in the morning and could cast freely from that list. Now I've thought about allowing that for prepared casters, but I'm worried that it will unbalance them towards spontaneous casters.
What I was thinking was allowing spontaneous casters to "weave" their spells like AE casters could, so that you could trade down a level two spell slot for 2 level ones, or trade up 3 level twos for a level three slot.
That way it gives spontaneous casters a little more versatility over their prepared counterparts. Thoughts?