Alien/Fae character would be good for this. I like the idea, but it'd need to be treaded carefully. I don't wish to live in the timeline where "Wizard 2" gets added to the game. This character should also be fun to play, as well as of course fight. Or else nobody will play them. So there needs to be stuff to do outside of reacting to stuff the enemy does and spitting out the appropriate projectile. I wouldn't know where to go with this off the top of my head but if I think of something good I'll let you know.
Viewing post in Bullet Hell Character Ideas?
A fairy would be neat. You also bring up a good point about having non- projectile options. One option might be a long range grab that you could use to throw enemies into your projectiles from afar. something like lasso, but better, but preferably not dumb like zephyr. Chaining grabs by throwing your opponent into your projectiles sounds fun. If there are any melee options, they should be really slow or small else the character would be too oppressive, but that would at least give them extra setup or defense.