Quick Test Results
Downloaded HE, first enemy golden campaign vs first enemy, each line is a different weapon:
Normal Damage, 50% Crit, 50% All Damage.
286, 407, 440
693, 966, 1152
1077, 1610, 1406
This is not much, but we can safely say that Crit bonuses are eclipsed by all damage bonuses. The latter work on any kind of damage (crit bonus found on equipment only works on weapon based damage), have no ceiling and are always active. With crits in vanilla you have a chance to deal ~20% more damage, while for example a maxed Eugene's Axe has a 70% All damage bonus.
Assuming an impossibile 100% crit chance, you still have 3.5 times the damage that also works on spell based CAs.
I'd say a nerf of % damage bonuses is needed, along with the the boost to x1.5 crit multiplier and a very big increase to crit chances on item modifiers