I've been refraining from posting my thoughts on this one until I've felt like I have the time to do so without interruption.
Forget the critical apathy, because it's important but it isn't the biggest issue. Forget the potentially middling sales, because they're important but they aren't the biggest issue. Forget how half-baked the game is in fundamental ways, because it's important but it isn't the biggest issue. The biggest issue with Mass Effect: Andromeda is that its cast failed to impress. At their best, BioWare games center on characters first and foremost. They build stories around their characterization and develop lore which will make sense in context. That's not to say the gameplay doesn't matter, because it does, but get 100 modern BioWare fans in a room together and I'd be surprised if over a third of them cite anything other than the games' cool characters as their #1 motivator.
Having failed by this metric, Andromeda is unlikely to leave a long-term impression with all but the most hardcore segment of its player base. Were the game's characters intrinsically flawed as concepts? I can see an argument to be made for that in some cases, but I'd wager the problem is with the writing instead. But that's not what this message is about, so I'll move on. The lesson to be learned here is that for a Mass Effect game to be successful it needs a solid cast. This isn't rocket science by any stretch but it needs to be driven deep into the minds of anyone at BioWare intending to create a new installment in a beloved-but-tarnished franchise.
It is my belief that, with the relative failure of Andromeda, the number of potential settings that BioWare can reasonably entertain the notion of building a game around have slimmed significantly. Although to some the very idea of a game set in the far future and in another galaxy was immediately unappealing, I don't think there's much salvaging that idea even for all those who went into Andromeda with wait-and-see mentalities (or even downright enthusiasm). There's always an exception to these conversations -- I personally know a handful of people who really, really liked Andromeda -- but on the whole I believe BioWare has rather cornered itself into needing to sever ties with a troubled experiment.
The idea of a prequel game never appealed to me, and judging by surveys from several years ago it appears that many other BioWare fans felt the same. But now? Now I'd say it's even less appealing. There's a pall of doubt over the Mass Effect franchise in 2019 and it needs to go boldly, not backwards. Most importantly, it needs to reconnect with the characters that millions of players adored. Charting unexplored space with a brand new cast is exciting on paper but Montreal tried that and it didn't exactly go as planned. I don't think it would be wise for BioWare to attempt to tantalize the fans with another stab at a brand new cast until folks have returned out of love for what made the trilogy so successful.
How, then, can we move forward directly from the events of Mass Effect 3? Speaking as someone who chooses Synthesis and is well aware they're in a minority on this one, it isn't with glee that I say this but the writers really ought to just canonize Destroy and be done with it. More fans are on board with it than any of the other endings. That's been patently clear to me for years and I reckon it has to be all the clearer to the people who created the game. Title the next entry "Mass Effect 4." Make it obvious right on the box what the game is supposed to represent. Remaster the damn trilogy beforehand to rope in new sales for the pending sequel. Don't start the game precisely where 3 left off -- skip ahead 15, 20, even 30 years -- but sprinkle in as much fanservice as you can conceivably muster, and write it well.
That's where Mass Effect is at this point. It needs a "Force Awakens" moment. Love them or hate them, the new Star Wars films began with a bang by catering to nostalgia out the wazoo. Being that Mass Effect has only been around for a little over a quarter of the time that Star Wars has, trailers with Wrex and Liara and Garrus and Tali and EDI aren't likely to inspire quite as much joyful shock, but by gaming nostalgia standards? Enough people will feel like it's a "Final Fantasy VII remake announcement" moment that BioWare will really make the necessary splash straight out the game.
None of this will matter, of course, if Mass Effect 4 isn't good. But in my mind it's the path most likely to right the ship for the maximum number of vocal (read: influential) fans at this juncture.