True, but some are inherently worse than others. I find Sage!Moulder is generally bad in combat due to his low magic damage. He absolutely needs Slayer later on to help with the monsters. Ewan's summons are always worse than Knoll's, Sniper offers nothing but being able to use ballistae for all three maps that have them, etc. But there's one class I think has zero reason to exist besides memeing...
Warrior is my least favorite class in the game; It takes all the worst stats about a fighter and amplifies them, while offering nothing but bows to a class that already has multiple 1-2 range weapons.