Everyone is talking about resists, you can put exactly the same enchants on cloth armour as on plate. My mages were basically immune to everything from mid-game onwards, I was more than happy to fireball myself if too many enemies got close. Still, I can remember a single fight where more than one enemy got close to my mages, that being one late game where I'd simply stopped bothering to summon anything because nothing could hurt me to any significant degree. If anything was able to hurt me, so what? For 4AP I can cast a spell that'll heal 2000hp.
Gear in general is far too powerful in DOS, the right gear makes any class overpowered.
Now there's a very simple reason for resists mentioned on Man-at-Arms characters. I suggest you check out the Weather The Storm talent. This is combined with the fact that plate armors come with 4+ resists instead of 0-2 and can be further enchanted to give even more. Also shields.
