After seeing how Firebolt works I am extremely excited to see what a Fireball can do in this game. Also slightly terrified of enemy wizards getting those spells without having a party formation to fall into at combat start.
Dont forget to use grease!
Two wizards can alternate using grease and firebolt, that makes 8 fireballs at level 4!
Or 10 if you take the extra level 1 spell slot feat.
But that needs two wizards for a fireball every turn before level 5.