I remember in oblivion when you swing a sword, especially a long/slow sword, the weapon slashes across the screen with a constant speed.

that's not how it works in real life. in real life when you swing something, you are applying a constant force to it, and as a result of the force (see Newton's laws) there will be a constant acceleration on the weapon. Therefore the weapon will slash across faster and faster while starting slow, rather than a constant speed. Try swing something, like a stick, you'll notice it.

I just figured this out a few minutes ago. Alas, that's why the sword swing feels weird in Oblivion and I couldn't tell why!

i don't remember how the sword movement was but warhammer's motion looks newtonian. Besides, slashing move happens in a second or less. Better physical implementation wouldn't do much difference.

Yeah! If the sword stops on swing into objects that would be epic.
example:
An enemy ducks your axe and SMacK it hits a tree and possibly gets stuck.
Your weapons bounce off the armor of your foe staggering them with a loud cLanG!


This is truly the only way to make these weapons feel more visceral and kinetic.

Nirn has no such laws.

Swords should bounce off of things. In fact, I think most of your blows should hit sword, shield and heavy armor parts like pauldrons, and only the last hit is animated to be a killing blow, kinda like Assassin's Creed. Its more realistic, and the simple way to impliment this into TES is just make it so that your attacks deplete fatigue instead of life (which would both give fatigue an actual purpose and be more like real one-on-one combat) and make the health bar smaller compared to what it used to be, that way once their so tired that their failing to block blows it isn't more than 3 or 4 hits until their dead.

animations surely have improved over oblivion

Improving animation doesnt' mean they are aware of this issue. We need to somehow let them know about it.

Physical contact of the weapon with the environment would be great, especially since that would also limit the use of large weapons in small areas; they could have an overall greater range, theoretically an advantage (as long as the enemy is actually pushed back slightly with each hit / everytime the player/large-weapon-wielder blocks, so that it doesn't become a face-hugging-fest), but making it harder to use the weapon inside small rooms and such. It'd also mean that I hit the enemy no matter where exactly he is as long as he's within the swing range; in oblivion I had to actually aim at the enemy. It also means that, if there's a friendly fighter, I could chose to slash from the different side in order to hit only the enemy - the weapon would then get stuck/bounce off, not putting the friendly at risk (or I could thrust/attack from above, depending on the weapon and on how much control I have).

We'll see how it turns out this time... Perhaps they went with a better system, or perhaps they're still at a basic system like Morrowind's/Oblivion's, just with two weapons.

this close to release?
if it's not already in, there's no time to add it.

Actually, that's not exactly true. (about the constant acceleration)

You see, there is a limit to how fast your arm can move (and it reaches that point fairly quickly), and the amount of force exerted by your arm on a sword differs due to differing joint positions and such. The whole thing is enormously complicated, and properly modeling bio-mechanics would have an extreme effect on performance.

believe me, when you are swinging a long sword, your arm moves fairly slowly because farther from the pivot point (your torso) faster the angular velocity. I still suggest you to find a long stick and swing it, and see how it feels.
but I do agree with you that due to the limit of your strength, you can't accelerate up to a certain point, but still, you have to accelerate from 0 speed to 60mph, through 10 mph, 20mph, 30... and so on. you just can't get there immediately like in oblivion.