I think a lot of people tend to overrate Morrowind by ignoring or brushing over its problems.
Honestly this is such a meaningless claim to make - you can say this about every other game: people enjoy it and rate it highly because they brush over or ignore its problems. Why do they ignore a game's problems? Because it redeems them, plainly.
Obviously, every game has issues. Some have more, some have less, some issues being more glaring than others. Many of these issues being purely subjective, of what one may claim is ruining the game may enhance it for another, but yet there will always be at least some remotely objective ones (objective in this sense, aside from strictly technical issues that have no redeeming values, would be aspects that are considered problematic and/or inferior/improper even by people who generally favor the game, ie. the target audience).
What matters is how individual aspects of the game end up being interpreted and remembered by the people who played it: There's the concurrent perception aspect, of how you feel directly when playing the game, and a retrospective perception of things you noticed and thought of it afterwards, when not playing it. In an RPG, an aspect like combat, can be viewed as one of the significant chunks of "gameplay". You can divide it into its strategic, tactical, action aspect from a purely deconstructive mental point of view, and then recognize that it also applies immediate perceptive bias to the concurrent perceptions even with aspects like presentation and visuals of it. If the action combat is lackluster, unresponsive, it might not necessarily taint the whole aspect permanently negative: a game can make up by having alternate options, or by redeeming its strategic and tactical aspects. And then the strategic aspects of it can tie in well to a game's exploration aspect, or character building aspect. It's all part of a larger piece of a cohesive combination, and not just a count of individual "good" and "bad" things that the game offers.
The end perception of the experience lies then on the sum and combination of its aspects: People will downplay issues in terms of importance, while still acknowledging their existence, because they didn't undo the game's overall enjoyment either in concurrent or retrospective perspectives. And if you sum up all the aspects of it together, a person may "overrate" it (a purely subjective claim) by not paying attention to issues that some would see as "glaring" - not because they are ignorant of it, in a fanboy-ish way simply pretending to not acknowledge the existence of therein, but rather because to them, they didn't affect the entire experience. And when the entire experience has been rated overall positive on all or most aspects, the final rating will be high. This is just how rating things works.