When we compare things we generally compare things that are alike. We do not usually compare things that are unalike ("apples and oranges") because such comparisons usually yield little in the way of useful data. We either need to compare the chance-to-hit of both games or the damage dealt of both games.
Morrowind's chance-to-hit was determined by a combination of player skill (one needed to aim competently) and character skill (assuming one had aimed properly, the game proceeded to compute chance-to-hit based on character skill). Oblivion's chance-to-hit, on the other hand, is controlled solely by player skill. And this is why Oblivion's combat system is often referred to as mainly first-person-shooter combat. Character skill is not a factor in a character's chance of hitting a target.
Oblivion's damage dealt was determined by character skill in both Morrowind and Oblivion.
In Oblivion the chance-to-block is also controlled solely by player skill, making this too a first-person shooter combat mechanic.
What can we conclude from this? Both games feature hybrid roleplaying/first-person shooter combat. There is, however, a significantly higher percentage of first-person shooter combat in Oblivion than there is in Morrowind.
Weapon skill does not determine damage dealt in Morrowind, not at all. It really doesn't. Strength does, but weapon skill does not. In Oblivion strength also affects damage dealt, but so does weapon skill. Again:
In Morrowind, weapon skill determines chance to hit, and only chance to hit
In Oblivion, weapon skill determines damage dealt, and only damage dealt.
Neither of those are a more RPG-oriented system. Yes, you choose when to block in Oblivion, but it breaks up a system of click as fast as you can and in Morrowind, you have fancy footwork to do for the different attack types. In Oblivion, you have one type of normal attack. There's a little less player skill. Yes, different power attacks also do different things in Oblivion, depending on which type of power attack it is, but Morrowind's power attacks do, as well, by building up on the original fancy footwork system. Overall...
Morrowind-weapon skill determines chance to hit, different regular attacks based on player choice exist, different power attacks based on player choice exist
Oblivion-weapon skill determines damage dealt, only one type of regular attack exists, different power attacks based on player choice, but character skill to even unlock them, exist, can choose when to block
Morrowind:
player skill based-different regular attacks(vary in damage dealt), different power attacks(vary in damage dealt, depend on player's ability to gamble on chance to hit vs. damage dealt), aiming
character skill based-chance to hit, chance to block
Oblivion:
player skill based-choose when to block, different power attacks, that require character skill to unlock, however, aiming
character skill based-damage dealt, efficient-ness of blocking, ability to use different power attacks
How is one to argue that one is more player skill based than the other? They break just about even.