I just made two skills legendary (enchanting and smithing). I put a bunch into my light armour tree (have all of those except the last one), and my armour rating is 775! Awesome. I'm going to start playing on Legendary difficulty now. It's going to be fun! All my armour and weapons are already enchanted so I'm good on those. And of course have Dragonscale armour.

Armor cap is like 667, so you are wasting a bit there,

I know that but before it was definitely under that. Like 400-something, maybe? I could have paid more attention. They should remove the cap, though.

Why? You should always be able to take at least some damage. The cap set that at 80%... or is it 85%. Maybe that's Magic Res I'm thinking about.

None the less, 15% or 20% is still an acceptable limit. Otherwise you eventually become immune to damage. Where's the fun in that?

max out your enchanting/smithing/alchemy and you can have well over 1K armor with no perks

The cap equals 85% damage reduction (IIRC). If they removed it you'd become invincible.

It 567, 80% damage reduction.