In the game Valkyrie Profile there was a nifty thing they did with magic users where depending on what kind of rod they carried and how many action points they readied, they would be able to cast different versions of the spells they had ready. The base spell, a powered up big version of the spell, or if you had the right rods, a massive High Magic spell of the same element.
I liked that idea and I think it would be a good one to adapt to tabletop.. probably specifically to tinydungeon since I think that's the one that's most straightforward to play and probably easiest to bolt a new magic system onto.
If I could get players incanting cool magical phrases like
"Surely, thou canst feel it! Thy days are numbered! Thy death is at hand! Crystal Strike!"
I would absolutely reward it.