Mass Effect never fulfilled the potential suggested by the first game. The greatest crime of that series is that ME1 never really got a sequel. It was rough, but it could have been improved upon. ME2 and 3 chose to be something else entirely.
Even aside from the mechanics like planet exploration and inventory management, the feel of the story and universe changed from 1 to the other two. ME1 felt Star Trek or Battlestar Galactica, 2 and 3 felt more like generic military stuff but in space. I think people still agree ME1 had the best main quest in the series and is still the best introduction to the universe.
And as for Andromeda's original ambitions for doing an Elite/Star Citizen-level game, I think that would have required them to go in knowing it would be a GTAV-level undertaking in terms of budget and time, at least. The issue with making that kind of game with a real storyline and everything, is that it pretty much takes a AAA publisher wiling to go all-out. Even worse, the idea hasn't definitively been proven to be workable. On a tech end Star Citizen is still in development and Elite is trudging along with updates. No Man's Sky also did some damage to the idea in the public eye. Despite that, developers are still trying. Ubisoft is trying to make Beyond Good & Evil 2 and StarLink games with cosmic proportions.
At that point you could set the game all on one planet and get rid of the Normandy, the ship's crew, the Relays, the galaxy map, etc.
Mass Effect isn't Blade Runner or Interstellar, it's Star Trek. Going to strange new worlds, meeting alien races, solving ethical dilemmas, and uncovering the secrets of the universe are what Mass Effect was built on.
It's like me saying I would like Destiny if it was more like KOTOR and less like Halo; sure I might like it more, but at a certain point it ceases to be Destiny and becomes something new.
The real issue here is that more developers need to be making space RPGs. There are different directions a space RPG could go for and Mass Effect has chosen one -- the Star Trek angle.
I think when people say they want the "detective game" or "bounty hunter game" from Mass Effect what they really want is a space western. They want a Han Solo game, a Boba Fett game, or a Cowboy Bebop game. A game where they get to make a buck by chasing jobs all over different planets while dealing with various colorful and unsavory characters and possibly dodging/dealing with the law. That's pretty much the basis behind the Elite games, but I think people want to see something like that with a pre-written storyline and characters.
Yeah, Mass Effect could do that, but so could another game.