Morrowind certainly isn't perfect, it's easy to find flaws like I remember it having a nightmarish journal, combat could easily have been better, etc etc. Though reading this is head scratching, I'm all for people having varying opinions but there is a distinction between opinion and, well gibberish.
First I read the first two paragraphs and every point in it is moot at best.
May not level up enough and the next quest may be to difficult.. Good, challenge is something sorely missing from games these days in so many way. Besides those difficult quests will be waiting for you if your character is to week, flawed, ill suited or if you the player lacks the skill to immediately rise to the occasion. This is also why Morrowind gives such a great sense of accomplishment far greater than some flashing level up sign or getting a new flashy move from checking a box. Something that once used to slap you around and make you run for your life becomes a challenge then tough then eventually you can beat it down without breaking a sweat and that's another one of those moments where you realise "damn I'm strong now, progress" until something later puts you back in your place. You start off as powerful as a homeless beggar with a wooden spoon but can eventually end up powerful enough to fly through the air in heavy armour shooting out lighting. The only flaw here is that once powerful going back to low lever areas later on that you avoided or missed will offer little to no challenge.
Using a trainer makes things to easy (talk about swinging to the other side). Training costs money if I remember right, to get money you need to....do I even need to finish this one.
Reading further I considered soldiering on.
So onto, not enough distinction between classes. One of my favourite things about character progression in Morrowind, just because one has the text "Mage" or "Thief" on a stats page doesn't prevent you from picking up a sword and armour and learning to use it (or a lockpick or spell), though it can have detrimental effects if I remember right, like wearing heavy armour while trying to sneak or it slowing one down due to a lack of something. Blurring the lines between classes is great. it allows one to stay purely a Mage, Thief or Fighter if you choose (to your detriment) or branch out and be more diverse and capable of taking on challenges in multiply ways, keep in mind this is a game where you only have one character, it's not like you can make your thief pick the door then have your fighter run in for the battle. There are loads of games which arbitrarily won't allow your "Thief" to wield a sword, if that's what you want you're in luck, elsewhere.
"Consequently, after some time you excel at everything and the existence of different classes loses its meaning." That's a quote, and I consider that a great positive in a long expansive game with many ways to do things even before considering the fact you have only a single character. Infact I consider it quite an accomplishment that a game that allows you to become master of all trades still manages to retain replay value.
Getting hard to stomach at this point. Onto the next paragraph where moaning about a Thief not being a killing machine starts things off. Really here's another great swing, from moaning about there not being clear unsurmountable barriers between classes to moaning about a thief not being a killing machine.
Moaning about starting low and having to get better seems to be a running theme here "character walks to slowly until you get something to move faster" etc. Again this progression from peasant to demigod is how this game gives a marvellous sense of achievement and progression along with the feeling that you've earned it. Some people prefer games that start off "awesome" and just get more "awesome" and even want an "awesome" button so when you push the "awesome" button "awesome" things just happen all the time, those games are out there, anyone is welcome to stick with them.
It isn't long before it moves on seemingly determined to display a complete lack of technical and arguably general knowledge.
NPCs say the same thing over and over. Yes, the problem here is called time and money, real world constraints hindering fantasy, studios have budgets to deal with and only have so much time.
"..models are ugly... didn’t the game’s designers see Baldur’s Gate or Icewind Dale?" Yes lets compare an old 3D game to 2D games (some of the best and biggest budget 2D games no less) and moan about how more time and money wasn't put into making fully meshed out 3D character as intricate as a drawing, or wait that's not what they're moaning about because it hadn't even occurred to them these things take work and don't magically appear and desired. All while ignoring the implications this would have on hardware requirements from the future to run it.
While it's not hard to find flaws in Morrowind, or any game, this is a load of nonsense often arguing with and contradicting itself (takes long to get places listed as a negative, and the loneliness/isolation as a positive. Loneliness only happens over time so if you could just whisk off to the next destination that loneliness/isolation wouldn't be there), it's worse than nitpicking coming from someone who didn't even bother with putting a (title)(/title) on the page.