The problem with all this is the amount of empty space to put in open-world environments seems to be a really subjective and divisive issue. This whole argument reminds me of the sailing in Wind Waker or the horseback riding in Shadow of the Colossus. Some people found that stuff boring but at the same time it succeeded in eliciting a sense of scale and isolation.
Mass Effect 1 in general is very confounding because its development was extremely chaotic, and all its individual pieces are extremely flawed, but somehow it all still came together to create an attractive storyline and setting.
Unfortunately I think ME1 was a prime example of old BioWare Magic, whereby through a lot of adversity and scrambling to pull everything together in the last minutes they managed to make something that wasn't the most refined but was unique and special in part because of that necessity to get things done. But in doing things in such a way they never really got a strong handle on why those things really worked in the first place or didn't work in some cases. Uncharted Worlds worked for some despite themselves and the many flaws and shortcomings around them. I'm not all that convinced BioWare really knew what they were doing with them or ever realized why they happened to really work and resonate with some people.
I think that's all the more apparent given the fact that they completely ditched them in ME2 and 3 as they didn't know how to improve them or make them work with the tools/resources they had available so they decided to just not bother with them again. BioWare then and now is often feels quite reactionary when it comes to feedback and other major trends in gaming. They have a weird habit of making drastic changes and reductions in their games due to that where they otherwise don't need to or shouldn't. Choosing to cut instead of improving or refining. A good example is how how they gutted ME2's romances and certain characters at the last minutes due to fears of Fox News after the reaction to the ME1 sex scenes.
That lack of understanding became even clearer in Andromeda where both their own desires and those of ME1 fans wanting a return of exploration they went down the route they did with that game. First they wasted years on procedural tech to create dozens of worlds for players to discover and explore which should have been clear from the start wouldn't work with their style of story/content driven games. Even after ditching that the end result still completely missed the mark and we got these bland open world maps that lacked any real sense of discovery or wonder as they just copied many of the same hallmarks and tropes of every other open world at the time. Mechanically and visually they were quite sound and well done, but outside of that their overall design and implementation was pretty terrible and showed a fundamental misunderstanding of what it meant to explore a new world and discover new things. Not to mention just the overall pacing and structure of levels and locations that made the ME trilogy so good which just wasn't possible in these open world type games.
I'm definitely the latter. Barren worlds do absolutely nothing for me. The stuff that excites me about Mass Effect is the lived-in universe and the melding of wildly disparate cultures. There's a Kaiden line from the first game that sums up what Mass Effect is to me:
"We finally get out here, and the final frontier was already settled. And the residents don't even seem impressed by the view."
While the terrain and level design of the Uncharted Worlds was quite barren and rudimentary the whole point of them was to show exactly that the galaxy was not empty. It was full of life and activity even on the most desolate and seemingly untouched planets. You had unexpected pirates, colonies, secret bases, communes, ancient relics and so on. The galaxy was new to humankind but even on the most remote and seemingly desolate worlds we weren't the first to traverse them.
It's understandable that the execution of those worlds left a lot to be desired for many people, but I don't think they were fundamentally flawed or in opposition to the style of story driven game many people want focused around alien species and interaction, just held back by the tech at the time and resources BioWare was able to commit to them.