There's precedent for off-hotbar skills, though. There's multi-colored Carbuncles we never got to see before. There's an entire school of sword skills that we don't have access to. Why not 1.0 spells, then? Why not waves of fire, or balls of lightning, or any number of things imagined?
If you write it well enough, people won't care what you do with it.
If you write it well enough, people won't care what you do with it.