I think there has been a HUGE improvement in balance on the latest test version, but I think that the post you made about the weapon slots and the damage they inflict it's a bit too exagerated, don't you think?
I mean, weapons that kill in 1 shot?? that's just too much... I prefer to shot 2 or more projectiles to the enemy than to be killed in the back with something I don't even see before dying, heh!
I think that if we manage to make same slotted weapons to work similarly, we will be able to make them use very similar amounts of mana for every class, but we might need to fix and even discard some of the actual weapons, depending the class characteristics we discuss and settle here.
I think the fighter should be a melee fighting guy, he has melee weapons mostly, but like 2 projectile weapons, maybe the darkness missile to distract and blind enemies to hit them easily.
The cleric could have both melee and long ranged weaponry, meaning he has both melee and mid-long ranged weapons.
The mage just uses long ranged weapons (no melee), and makes low damage in the lower levels, but as he increases his exp level, he willl deal critical damage for other enemies.
The marine could the most hitscan weapons in the game (pistols, shotguns, etc), which give him a somewhat advantage from other classes, but his weapons having great accuracy, deal low damage (no matter it's level), he also has some medium, long range weapons too.
The heretic could have magical weapons that make much spread damage, that increases as he advances in experience level.
The witchaven could be similar to the cleric (has both melee and mid-long range weapons), but the stronger weaopns are few, (since he has those homing projectiles), it could be a tricky attacker.
That's my thinking about the classes, as for a general formula, I think we already have some of them, but we could adapt them better for the gameplay.
BTW, do you think these weapons are still to unbalanced??