Morrowind combat is based on dice-rolls, while Oblivion and Skyrim are not. That's why it gets mentioned in connection to MW being a bit more difficult.
If you are playing Morrowind and expecting PoE or Diablo... Well that just makes no sense.
The games have nothing in common when it comes to game mechanics, or design and implementation of how to make progress. It's comparing apples to oranges... But clearly that seems to be root of your issue, because you completely ignore all the advice here about how to enjoy an open world TES game where you have free control to create the rules as you see fit.
TES isn't about min-maxing, being optimal, over-thinking stats, or even doing things correctly. Just explore and create your story.
If disabling the expansions is what will help your game, go for it. But if the assassins ruined the game for you because you couldn't stop selling the gear (despite there being many ways you could fix that) than you're going to discover the exact same problem through the entire game, just in other forms.