Now, a lot of this i knew cuz i was in the alpha but i'm gonna write everything out as if i wasn't because A: it's just more comprehensive that way, and B: I can't talk about the alpha anyways

, but i do want to mention this: Our feedback was definitely heard. So! Here's everything i've figured out by watching e3 footage.
Let's start with controls and basic mechanics(controls will be written as if for an xbox controller as that is what i use):
you of course have movement on the left stick, a sprint button. right stick controls looks and holding L2 locks onto a target and then your right stick controls your attack/block directions. You can switch targets without dropping your guard. Light and heavy attacks are bound to R1 and R2 respectively, and you can guard break by pressing X, and dodge by pressing A. Heavy attacks are slower, hit harder, can be cancelled to trick opponents and deal small amounts of damage when blocked.
You can parry by pressing R2 at the proper time. You also have a wide sweeping attack. You can also combo attacks together, and each hero has unique abilities (such as the Warden's shoulder bash, or the Raider's body check and charge) and feats that supplement the base combat actions (such as the heal feat that will likely be everywhere in the campaign), these feats are bound to the d-pad. You can also fall on top of enemies for a 1-hit kill but be wary as there is fall damage.
Combat:
When you attack an icon appears in the direction you are attacking and flashes right before it hits, and red icons appear when an enemy you are not locked onto attacks you but these icons don't flash. Guard breaking also causes a red icon but only briefly appears before it hits. You can counter someone's guard break but if you don't then the guard breaker can push/throw you in various directions or get a free hit on you. If the guard breaker does nothing you can eventually break free from his/her grip. Parrying also allows you get a free hit in. If you block an attack, you very briefly block all 3 directions at once, and if your locked onto one enemy and another enemy attacks you you only need to block in the direction of that enemy. Dealing a killing blow with a heavy attack allows you do to do an execution animation which humiliates your opponent as well as heals you.
Parrying and guard breaks are basically your anti-idiot options, if the opponent never attacks and only blocks, guard break him for a free hit. If he only attacks, parry him for a free hit.
You also have a stamina meter to manage, every action seems to drain stamina except blocking and parrying from what i can tell but getting blocked drains more stamina than a successful attack and getting parried seems to drain even more stamina than that. Also the new stun attack that seems to blur the camera drains a LOT of stamina. Parrying either gives you stamina or stamina regen continues while you're parrying an attack, it wasn't clear which from the footage i could find. Being completely drained of stamina slows your attacks and makes you vulnerable after attacking. You probably wouldn't be able to sprint either. You really, REALLY don't want to be out of stamina.
You have a 'revenge' meter. This meter drains when you are not locked onto an enemy and fills as you block and take damage. When activated it knocks any enemies who were attacking prone, allowing for free hits, and gives you more damage, gives your attacks hyperarmor (uninterruptable), and may also give other defensive benefits. Once activated it drains rapidly until gone. This strikes me as a concession for dealing with multiple attackers as you could block a few attacks, then revenge to knock them all prone allowing you to escape or mount a counter-attack.
Shields:
While you don't use a shield in any of the gameplay, your opponents do, and some of the footage shows a viking ally with a shield. So i've been able to deduce a few things about their use.
Shields do nothing special normally, you don't seem to be able to say, block a different direction than the one you are attacking. But they do seem to have unique guard breaks, the viking could be seen pushing an enemy with his shield after guard breaking (similar to the raider's charge), and you seem to be able to enter a turtle animation where you are blocking all 3 directions at once but continuously drain stamina until you leave the animation (seen here:
https://youtu.be/Q4Su36mTnRQ?t=83).
Final result:
In combat you will maneuver up to an enemy, constantly shift directions to keep your opponent guessing, before you either feint a direction and then light attack, or heavy attack but cancel into a parry or block, or guard break suddenly. Dodging away or around the enemy or perhaps parrying him before going in for another attack. If he gets help, block the attacks until you can revenge then either go in for the kill or flee. Once your enemy is low you could finish him off with a heavy attack and then execute him to heal you so your ready for the next challenger.
That's all i got, feel to post anything you think i missed!