From reading your post I can see you haven't played evils much.

Paladins didn't just get downgraded, they got changed. Tell me when you are playing an ap or necro and a paladin manages to send the whole cursed group home that they got downgraded.

APs didn't really get upgraded. They just got more variety. Previously unholies other than axes just weren't worthwhile. Now they are viable. The new "ap spells/skills" are not new. They've just changed the way you get them. Previously it was by killing a load of people and taking their souls, and had nothing to do with level. Now it has a level based element and less of a soul based element, forcing ap's to rank up to benefit from them.

Duergar may have resistances, but they have low mental stats, which makes them vulnerable to things in other ways.

Most aps don't become powerhouses. Most necros don't become liches. Evils have more maladictors but goods have paladins.

You sound like you've only seen one side of the coin properly. Having played both sides and most cabals, I think it's fine.