I can see Spellfire Adept working on Paladin.
waiting for a crit then smite. adding +4d10 on a smite few times per day might be worth a feat.
bear totem barbarian could have good usage of Bloodlust,
it was capped in 3E also, at 10d6, but that was probably due to autascaling with levels.
PF1 did have metamagic for +1 spell level that raised max damage dice by 5, Intensified spell feat, so at 15th level you could use 4th level spell slot for 15d6 fireball.
maybe use a faster half caster house rule?
left table is default, right table is with faster progress.
SP value is about the same,
less total spell slots earlier, but you get to your 5th level spells as fast as a full caster.
or just make upcasting worth it.
IE: fireball:
2nd level evocation, fire
Action
150ft range
dex save
deal 5d6 fire damage, 15ft radius. half damage on a save.
you can reduce radius by 5ft to increase damage by 1d6.
if you reduce radius to 0, it becomes ranged spell attack that deals half damage...
maybe another invocation:
Improved pact of the tome. requires warlock level 5+
pick a number of spells equal to your charisma modifier from any class,
spell must of of level of your pact slots or lower(max 5th), you can cast those spells with your pact slots.
I generally hate the idea, even spell slots are kind of dumb in the end.
Spell point is the best variant to me.
but, since this is a +thread...
more spell slots would be required for loss of flexibility, there is a good chance that many of spell slots will not be used during any given day...
seems like a good idea,but please no.
If I never see re-roll mechanic in 5E it will be too soon.
I will replace EVERY re-roll with flat +/- 5 to the roll.