About a week ago I started a character on master, and let me say it has made this game 10 times more fun than it was before. I'm proud to say I have made it all the way to level 29 without having to turn down the difficulty once. But I am starting to run into some problems now. There is a lot of enemy that can 1-3 shot me no problem and it starting to get a little frustrating. I am running a duel wielding, heavy armored warrior/sneaky hybrid. I do plenty of damage from sneak attacks and power attacks thats not really the problem. It's his durability.
For reference im going to include some of my stats,
318 armor rating, this is including the bonus from the lord stone
my resistances seem to be pretty good with the supliment of potions and the bonus from the lord stone.
I guess what it really comes down too is, does reaching the armor cap really make that much of a difference? I am about halfway there and I mind as well be fighting naked, I die in about the same time anyway. I have a set of blades armor smithed to superior ( my smithing is quite low, I only use it for the weapon and armor upgrades. I do use some smithing equipment to jack it up high enough for it to actually be somewhat useful though.) this is currently the best armor available to me.
I am fairly balanced in my skill distribution with 74 heavy armor, 79 one handed, and 84 sneak. The only other skill worth mention is my alchemy which is at 49 ( I do make quite a bunch of health potions to make up for my extreme squishyness.)
At this point I am actually kind of upset I didn't go with light armor. They look cooler, have better perks (imo) and to top it off would probably work better ( due to easier dodging, less carry weight etc.) The idea of my character was to make a duel wield warrior that could toe to toe with stuff, and still sneak around and assassinate for fun, but hes turned out to be just an assassin in heavy armor.

What am I doing wrong? Any tips would be greatly appreciated.

