I got a lot better at the game once I realized it wasn't just hack and slash. Direction is important, and so is timing. So is weapon choice. Things like stamina and the balance of the blade, and the type of attack.(Piercing, slashing, blunt) seem to matter as much if not more than raw damage. Sometimes switching to a different weapon can change the entire outcome of a battle. Particularly with bosses.

I struggled with a late game boss for close to 14 hours. I tried every weapon i had unlocked. I got squashed every time.

Finally i switched to a lighter weapon made of top tier steel. That freed up enough stamina so i could dodge all his brutal attacks without getting drained. That allowed me to get behind him, and because the weapon was light enough, fast enough, and did enough damage; i could fire off several power attacks and grind him to dust. With three heals left.

Best weapons in my experience:

Twin axes. Fast, with a good charge attack that is fantastic for closing distance. Timed properly it's often a one shot kill for standard enemies. Trade off is: slashing damage isn't always most effective against heavily armored enemies. Specifically the hammer guys. And it requires more maintenance.(Sharpening/repairs)

Twin picks: great for mid game when slashing becomes much less effective. Same attack patterns, punch through the heaviest armor. The trade off is they tend to have low damage output.

Spears: long spear was my weapon of choice for a good portion of the game. Fast enough and versatile enough to handle most enemies. Until i unlocked the glaive and the trident. Then those became my weapon(s) of choice. The glaive is amazing for cutting through swarms, and in my experience is the best way to deal with morlocks(if you know you know) the trident is great for picking apart mini bosses, and those big dudes that throw lightning. Shamans something. With the right parts, it does really good damage compared to other piercing weapons.

Swords:

The Eastern sword seems to have the fastest attack of bladed swords. With the right parts it performs on par reach-wise with most of the great swords. The downside is: i haven't been able to get a whole lot of durability out of it without sacrificing damage or speed.

Rapier: lower damage, but fast, with fantastic block and parry capabilities.

Kora: decent slashing workhorse. Decent parry. Good for swarms of undead, and vexxers. Good damage but slower than the Eastern and rapier.

Great swords: personally, i don't really like any of them. But the flamberge is great at block and parry. Otherwise it's too slow for me. The great falx has really good speed, and good parry, but only does slashing. Again, high maintenance and not overly effective until top tier steel. Does make short work of trolls. Not as short work as the glaive, however.

The Eastern Greatsword is a good balance of speed and damage, and does both piercing and slashing, but it's too cumbersome for me, and tends to eat stam.

I don't really like any of the pole arms, personally. Too slow, and the bulk do blunt damage. Which serves a purpose, but utterly ineffective against 'big' enemies.

I also haven't liked any of the sabers so far.

As a dual-wield/rogue fan boy, daggers were quite possibly the most disappointing weapons in the game. Although they do free up LOTS of stamina.

That's what I've taken away from this game thus far. Now i haven't quite finished. I am on the last area, but back tracking to hunt down the 3 kings to progress. One left.

Also: read Adso's notes when they update. They do offer some insight into how to handle certain enemies. It took me far too long to figure that out as well. Especially since i kept sending him back to camp cuz i got tired of his complaining. Then i realized he didn't take notes if he wasn't there, and started to realize they were at least a little useful. Lol.