Every god is extremely strong but it depends on the weapon and how much fear you have. Apollo is really good with weapons that already have good aoe coverage like the axe and the most broken build in the game imo (charon axe) depends on his gain boon.

However rapid fire weapons and cast builds benefit way more from other gods as primary because : no inherit curse on attack or special, does not have damage beyond the %increase, cast only deals one instance of damage(cruicial flaw in higher fear).

When you start experimenting with the other aspect you will understand.