Fantastic art, love tactics games! I streamed this game a little so here are some of thips I had from then:
The procgen needs to facilitate player options, alternate paths should be DIFFERENT, otherwise theres no point in having branching paths and it should be linear
Environmentals will immediately enhance any amount of tactics, when designing environments make sure they are both positive or negative depending on positioning or character class
Simply adding item pickups with different uses (shields, damage, healing) will give unique utility to characters who don't normally have them
Giving the mage several spells will also enhance the tactics if you do a bit more with the projectiles
I would suggest making some projectiles friendly fire, while others are projectiles that can go through friendly units, this way you can add some balance to your stronger spells and enhance the tactics of positioning.
Over all very impressive for the jam! Good job.