Firesorc is very good, honestly feels better than light sorc because phoenix is so chill and A5 is brutal for light sorc. It’s a very good build, but not as good as warlock, mosaic, java, hammerman
below warlock/java/mosaic but it might be better than donk now
fireball and hammer kind of have comparable if dissimilar aoe but fireball lets you snipe some spread out monsters at range instead of having to stomp each, and damage isn't too far off
I think fireball has the edge because against heralds and bosses you can dump hydras+meteor+static, donk is one speed only
But still plenty of applications not so great, like undergeared chars, and just boring MF routes where a blizz sorc can stack more %mf and kill faster ex doing 10/11 trav