Some excellent points, remember that it is extremely rare to get over 80% resistances in the base game though
Depends on play style an character set up. If you use crafting, you really can get high resistances. I played the base game without any mods or cheats or whatever. My tank-mage had 200% fire resistance (cap) and an average of ~130 to all resistances. Perfect for healing with area affects between some enemies!

Crafting gives you: 25% all elemental resistances on armor, 25% all elemental on helm and 20% all on bracers. And single 25% on shield.