I found vanilla Skyrim way too easy. I can't even play it anymore. I had to self-nerf and purposely do things like only use iron, etc. Especially at high levels.

I have been using mods like deadly dragons, ACE combat, and Deadly Combat. Here is the problem:

If I play using light armor, a couple hits and I am dead. Sometimes one arrow will kill me. If I use a two handed weapon, I can't power attack because it gets interrupted by someone's fast attack and I get staggered and then hit a few times before I can even swing again.

I want o play using light armor, archery (but not sneak) and dual wielding plus some spells like restoration and alteration. Can you guys recommend a solution?

One more thing is that if I use sword and shield, after I block, my right hand does this weird bashing movement which prevents me from counter-attacking.

And are there any good lore friendly mods that add either high level creatures for late game, and/or make enemies level higher?

Try skyre. It changes the feel of combat. With the changes in the weapon perks, and bleed damage, it plays totally different. If you wear light armor, blocking/avoiding hits is still highly recommended. However, heavy armor, arrows are not much of a threat, though you are slower

http://skyrim.nexusmods.com/mods/9286//?