A few small~ish suggestions for some spells, mainly to improve their usability
Drain-Type Spells
Due to how drain-type spells work, their potential is pretty much capped. It's especially annoying with things like Rage and Dance, as the drains they have are often just dead turns.
I'd suggest making all hp-draining spells/effects, except for the OG Drain Spell, work off their base power alone and not factor in missing HP. This would make Love Sonata as well as some Rages way more appealing to use, in my opinion.
Surge
This is specifically for Mog's Dances - Water Rondo and Snowman Jazz. While making sense aesthetically, I don't believe Surge should be a ground-based attack. It's a problem for Surge, as it heavily reduces the reliability of the aforementioned dances in a lot of encounters, as quite many enemies are floating. If enemies aren't floating, a magic-based Mog can hit them quite well with Quake in the first place. I'd slightly decrease the base power of Surge to compensate.
Reflect
Reflect is always a bit of a contentious effect. It can be amazingly powerful, but there are a lot of factors to consider when using reflect. Most importantly: Does it do anything in the battle at hand?
I noticed that far more abilities than I previously assumed can be reflected. It'd be nice to have some sort of indication of that - like a blue dot.
Additionally, if desired to make reflect a tad easier to use, one could make certain buff spells ignore reflect. Safe, Shell, Float and maybe even Haste come to mind.
Fractional Damage
Is it possible to let fractional damage work on max health instead of current health? If it's possible, I think this would open up some interesting changes for some rage or dance skills.
That's about it. Thanks for reading and please tell me what you think.