For me it boils down to collisions and movement. First off, I hope they pour a lot of time into make combat a more visceral affair than it already is, especially since ES games have always been about intimate combat settings, as opposed to large scale combat settings with multiple enemies. I'm having trouble describing all the things I am hoping for, so I am going to just give you a play by play for how I imagine a next gen ES combat system.
My battlemage steps into a new cave system. The path ahead is dark, so I move forward cautiously. Up ahead, I hear a faint conversation. Never one for stealth, I draw my two handed sword from my back and stalk forward. I enter into a large cavern, where two bandits are talking by the light of a small lantern placed on a table; I immediately notice they are standing behind the table. I sprint forward and hit the right trigger (I'm an xbox player) causing a contextual action to occur where I kick the table with my foot and overturn it into the two bandits. It takes one completely by surprise, but the other had a high enough strength and intelligence value that he was not taken off of his feet. He draws a longsword from his waist and faces me.
Instead of charging right into the fray, he approaches cautiously, with his blade readied. His movement is much more natural and lithe, indicative of his more thief like fighting style. I step forward and swing with my sword as he simultaneously swings as well. Our blades collide in mid-air with a clang, but because I am using the heaver two handed sword and have a higher strength value, the bandit is staggered and he stumbles backwards by just a step. I take advantage of the opening and follow through with another strike, slashing the bandit across his chest. His health drops by half.
At this point, his other friend has gotten to his feet. This bandit wields a dagger and so he charges forward aggressively. Since I was focused solely on the first guy, I don't notice this bandit coming and he manages to tackle me to the ground, getting in a few stabs. An onscreen indicator pops up, telling me to wiggle the left stick to get the bandit off of me. I start to do so, when I see his dagger coming in for another strike. I press the RT when the onscreen prompt appears and my character grabs the striking hand and turns the blade aside, rolling the bandit off myself in the process. I gain my feet in time to block a strike from the bandit who I had slashed earlier. My blade takes an appropriate angle to match the incoming strike, and the blades clang together in the air. I press sprint down, ramming my body into the bandit, which because of my larger size and higher strength, sends him stumbling again. I follow up with a strike, which triggers a kill cam of me running the bandit through.
The effort of this fight has left me with little stamina, and I can hear my character's labored breathing. In the third person, he is slightly hunched and the physical signs of fatigue are present. Unfortunately, the remaining bandit is not. He has regained his feet and is again sprinting toward me. I swipe my blade in front of me, and the bandit stops short, dancing around the range of my attack. Each swing drains a little more of my stamina and eventually I hit empty, and I have to rest. The bandit sees his opportunity and rushes forward. I am doomed!
However, I am a battleMAGE. I press the RB, triggering my quick cast spell, which is a powerful fireball. With my free hand, I sling the flaming spell at the bandit, which engulfs him in flame and causes him to stagger backwards from the spell. My mana is nearly depleted from the spell, due to my lower intelligence and low training with destruction, but the spells in this ES game are much more destructive to offset the high cost; each one means a major difference. The bandit drops to the ground, dead and scorched. I set to healing my wounds with Restoration after the fight, and my character gives an audible sigh. Restoration spells cost less to use outside of combat and are more effective, so the small amount of mana I have remaining is sufficient to heal myself. My stamina is slowly recovering and so I spend a few moments looting the two bandits before I set off again and see what the rest of the cave holds for me...
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Sorry for the long story, but I hope that illuminates what I am kind of envisioning for the next Elder Scrolls. Basically, I think if they have a powerful enough machine (as they might with next gen) then hopefully they can make a game that is more about manuevering and thinking on your feet, as opposed to stocking up on potions, health, and just hitting your opponents with the best weapon you can get your hands on. The combat system as it stands now is so boring and bland, but hopefully with some improvements to the next ES game, they can add in more situational combat and also some QTE's to spice things up.
Also, and I in NO WAY want to argue this point here, but I included some mentions of attributes. I am thinking that adding attributes into the next ES game could give them the opportunity to utilize them more in combat, such as doing checks for strength and other attributes against your enemies values, when it makes sense to do so. This puts more emphasis on your choices during character creation. Maybe you are stronger, but then you don't have much agility (and maybe strength influences your body size along with endurance?) However, perhaps you forgo strength and instead choose to maximize agility, which makes you more lithe in combat and able to dance around your foes and possibly insta kill them with the right perk? Maybe you choose to balance strength and agility to have a more athletic bodied warrior who can strike savagely, but can't be quite as good in either as someone who sacrifices one to acquire more of the other. I see a lot of potential with a new combat system in place, in addition to differing dialogue options, and more unique attribute stuff.