Damage reduction is capped at 80%. If you are wearing all four pieces of armor, this occurs at 567 displayed armor rating. If you have 100 skill, all relevant armor perks, and Legendary equipment, you will need about 85 base armor to achieve this cap. This requires the Nightingale set for Light Armor (though Dragonscale comes close), and at least a Steel Plate set for Heavy Armor.

With the Lord stone, the required contribution for worn armor drops to about 74. This requires at least a Glass set for Light Armor, and at least a Dwarven set for Heavy Armor.

http://www.uesp.net/wiki/Skyrim:Armor

No, there is no reason to since every single character starts off with 100 skill, all relevant armor perks, and Legendary equipment.
Oh wait...

Amazing things happen when you stop using console commands and play at the intended pacing.

You completely miss the point, light armor and heavy armor is on par when it comes to damage reduction there is no reason to go above the stated 567 ( mages on higher alteration level get a spell that ignores 80% melee dmg for some times ) so when it comes to endgame you could ignore as much damage with crazy enchanted daedric gear with 1600 armor rating as with a mage that is arsed to cast such a spell once every 2 minutes, or a thief character.

Note: also if you skip the heavy armor you could avoid the nasty magicka cost penalty for spells while wearing heavy