Quote from Pietrak
A Wizard with a wand+source / 2h staff is ideal.
A Wizard with a slender, light weapon (sword, dagger, spear) + source is good.
A Wizard with a heavy 1h weapon is bad.
A Wizard with a massive 2h weapon is horrible.
A Wizard who is forced to wield a massive 2h weapon in order to maximize DPS (Skorn) is the worst nightmare.
Same analogy goes for the other classes.
I've been thinking a lot about this today and you're actually starting to win me over (but only VERY slightly).
I'd like to see a compromise. I would like to see that in your example, if you're using a wand/staff, you receive a 20% bonus to your overall damage basis.
The slender light weapon, is neutral, while the heavy items would be "allowed" (excluding mighty weapons) but would incur a 20% penalty for that class. Each class would have a list of weapon types that have bonuses/penalties.