I feel it's needed to describe my character before I go into detail about the issue
I am a level 42 Argonian I have maxed Blacksmith with a full set of light dragon armour at legendary status. I am an archer primarily (100) my light armour is 65 my one handed is 50. I have several perks in light armour 2 in one handed and all in archery. That is the relevant information I believe.

The issue I am trying to level my one handed combat but I run into an issue I go to fight tough guys like foresworn briathorns which from stealth with a bow I kill in maybe 2-3 hits no problem. At melee I try to engage them head on and I sometimes get one shot by a finishing move even if I am at 90%+ Hit points not to mention I have ridiculously high armour. This had happened before once with a dragon but I wasn't so well equipped and I was at maybe 50% Hit points so I let it slide. I am on the default difficulty which I believe was called adept.

I am not sure if that is intentended but it seems a bit much to get killed in one hit from even a tough enemy especially if I got best armour in game and I have like 300 health (I put quite a bit of my levels into my health like half or so.)

I think that you are too good at this game.
The Game says: Oh, yeah??
And you say: Yep, that's right.
The game says: SLAP!
Done.