I thought the mechanics in D:OS2 were a great improvement over D:OS with a few exceptions.
The big failure was the armor system. Having a party of mixed damage types is very inefficient because of it. Also having a melee guy with a sword that has added magical damage, that extra damage is a waste.
There is also another big imbalance in the game design. Physical / Melee is MUCH stronger than magic damage. Warrior skills are based on weapon damage, where as mage skills are just purely level based. Your melee damage will scale up much better compare to a mage.
To make matters worse, just about everyone has some kind of magic resistance. Even if an NPC has only 20% fire resistance, that is a flat out 20% less damage you will do the them. Physical damage doesn’t have such a reduction with the exception of a very few special encounters with highly physically resistant mobs.
Right now I have a vampiric lone-wolf warrior who’s normal, base attack damage is like 2500 pts. He also has about a 50% crit rating and currently 185% more crit damage. Its absurd. No mage build will ever touch that.