I think I had a similar issue with Healer in 3.3H. The last 9th level spells, like dragon cloud, would not show up in radial menu. The feats were there however.
Breaking up the menus by spell levels would BE an AWESOME idea. That's how the hardcoded spell menu is. I can't believe no one thought of it before...which leads me to be its might not be doable =(
If this is doable, this along with the recent changes to spontaneous spell casting menus, and all the other improvements (not having to select spells for classes that know their entire spell list)....the PRC spell system is just as good as the hadcoded one, its becoming much more manageable, kudos.