The leveling systems for both Morrowind and Oblivion were the same in that you needed to raise a certain amount of skills and rest to level up. Now if you are talking about enemy scaling that is a different matter entirely.
Also outside of specific spells such as levitate, I don't know what other gameplay features were missing.
Not just enemy scaling but loot scaling. This has often been called "leveling". In oblivion, where loot is placed is unaffected by where you are, just what level your at. In morrowind the best loot in the game did not scale with your level and was carefully placed in special dungeons for the player to find through exploration. All of this was missing from oblivion, loot just scales with your level and is the same everywhere. There was a mod called "myths and legends" for oblivion that added this element back in quite well.
Loosing levitate is sort of a big deal in itself. You also loose active enchantments, and the ability to passively enchant weapons. Polearms were also removed, though I have no idea why.
Dialog is massively oversimplified, before you could ask people questions about game or area lore.
Armour is split into less pieces giving you less control over mixing and matching, you also can't wear clothes under or over your armour. It might not seem like a big deal but hunting for a full suit of daedric armour or a suit made of lots of different pieces of legendary armour was a big part of the fun in exploring morrowind in the late game.
