delericho
Legend
The thing is that in most fields there are ways that experts in the field use to judge quality. Literature is judged based on the use of language - things like imagery, ambiguity, and so forth. The quality of wine is judged by things like flavour notes and complexity. And in the Olympics the more subjective events are judged by experts who are looking for particular skills and techniques being displayed.Quality is completely subjective, there is no way to gauge it so is pointless in really discussing it. The best you can do is identify what, to you, is quality and discuss why something is quality with those who share your views.
But the thing is that, once you get beyond the basics, for most laypeople the more nuances qualities are largely invisible - any of those Olympic athletes are so far beyond the rest of us that we just don't have the means to judge between a superb performance and a best-in-the-world performance.
But that doesn't mean that those nuances aren't there. Quality, by and large, isn't completely subjective.
With RPGs, given that it's still a fairly new field with fairly little established art, I suspect the markers of quality in design just haven't been established. (And, indeed, with D&D looming so large over everything else, there's a good chance that they may not be established - because it skews the entire question of what an RPG even is, everything else is pretty much defined either by how it compares to D&D or in reaction to it.)
So more or less the best we can say about 5e is that it is, indeed, a good RPG (and a good edition of D&D) - that sustained popularity basically proves that. But going beyond that, to questions of whether it's better than any other RPGs or editions, is hard to judge. By and large, we're just lacking the metrics by which to do that.