1. Yesterday I played Morrowind for the first time in my life so this post is not biased by nostalgia.
2. I'm also a casual player who likes combo-based combat a la 'Gof of War' or 'Devil May Cry' so no, even though I'm gonna talk favorably of Morrowind in this post I'm far from wanting to turn Skyrim into a diceroll-based RPG where character skill is practically all that matters.
Now on the post itself:
When it comes to combat, there is only one thing that is deal breaker for me: opponents not reacting when getting hit. This gives the impression that your hits carry no strenght at all and makes combat look bad and feel dull. Unfortunately, both Skyrim and even more so Oblivion suffer from this, the clearest example being 'normal attacks' which will never ever cause a physical reaction on your opponents.
Since in Skyrim is like this and in Oblivion was like this, I thought that this was a general issue with TES games. I was wrong. To my surprise, in Morrowind is not like this! In Morrowind, when you hit an opponent he always reacts by showing a small recoil. And man, it feels good! This feature, as awesome as it is, needs balance though since if any attack causes recoil, and while recoiling enemies can neither attack nor defend, then one could very easily win any fight just by hitting first and keep swinging until everybody is dead. Morrowind's way of balancing these recoils is to make opponents harder to hit. This means: your attacks can miss and the probability of missing depends on how high your weapon skill is and how much fatigue do you have when hitting. This is simple, elegant and it even makes sense. The only flaw of Morrowind was that opponent's didn't have a dodging animation. This make missing an attack difficult to swallow because, come on!, if the opponent is right in front of me without moving, how come my hits are missing? Add a dodging animation though, and the system would have been very very nice.
And a 2n thing Morrowind did well was adding mutliple damage figures for each weapon. Indeed, weapons in Morrowind have slashing damage, chop damage and thrusting damage. Depending on which move you perform (a slash, a chop or a thrust) one of this damage figures will be applied. Since different enemies were vulnerable to different types of attacks this mechanic made for a very interesting experience. For some reason though, in Oblivion and Skyrim all this disappeared.
So:
TL:DR/ what I'm proposing:
In Skyrim every hit should cause a physical reaction but, to compensate, opponents should be harder to hit (they can dodge your attacks).
Weapons in Skyrim should have different damage types (chop, slash, thrust damage). Each opponent should be specially weak to one of those.
Morrowind did both things above but for some reason next TES games forgot about them instead of improving on them. IMO, this is a mistake.