How do you feel about the premise not happening due to the Reaper invasion?

Wat?

I'm probably going to be willing to handwave this if necessary, but I do think there should be more than just Exploration behind this.

There's a ton of stuff to explore that's nearer and doesn't require flinging thousands of people off on a one-way trip into the unknown. And might offer some sort of return for any investors.

We're talking about what motivates people.  The whole of the Star Trek society was based on the idea of pure exploration... no threats of any kind apparent that drove them to explore as far out into space as they could.  Is it reasonable to expect that a "utopia" where everyone's needs were so well looked after, why would it be "natural" to look outward... why explore at all?

If the Andromeda Initiative is privately funded by "some rich lunatic" who just loves the idea of "going where no one has gone before" would the fact that a bunch of impoverished peoples object to it matter?  It hasn't stopped the likes of the Virgin and other uber wealthy individuals here in the 21st Century from doing whatever they please with their own money?  Why should it be any different in the Mass Effect universe?  It apparently didn't stop Jonah Elfeld from wasting a bundle of money on his hair-brained daughter... even as he was bemoaning bankruptcy because of the war in the ME3 Citadel DLC.  She seemed to be crazy enough to think about funding an mission to Andromeda... so maybe that's where all his money was going.  What about Rupe Elkoss... making a bundle on weapons sales... or a consortium involving Barla Von... who had insider financial information on all "the elite of the galaxy" and could keep all those transactions completely a secret (for a fee, of course)?

I'm not sure yet. It will depend on how it is explained in game.

I liked the Reaper War fan theory both because it provided a great excuse for going to Andromeda, and because it could be tied into the Asari Councilor's dialogue after Thessia. It also would neatly explain why there was no mention of it in the Shepard trilogy. It would then be a top secret project, rather than a corporate-funded adventure. Another benefit is that it would potentially get everyone on board, Quarians, Batarians, & Geth included.

That said it looks like the explanation they're going to use is that it was discovered that the Helius Cluster of Andromeda has a higher than usual number of potentially habitable worlds, and a long term goal is to establish a link (Mass Effect relay?) between the Milky Way and Andromeda. I can roll with that. I can also understand how breaking with the Reaper War gave the writers more freedom with characters' backstories. With a Reaper War exodus, everyone is a refugee. One benefit of not going that route is that you can give characters diverse motivations for joining the project.

Don't care much about it at all to be honest. It being unrelated to the reapers I really only see as a good thing

From a narrative point of view I much prefer the escape plan idea. It's a wonderfully dramatic backdrop and also kind of heart-breaking because Shepard did end up saving the galaxy. So they didn't have to leave their loved ones behind after all (they are very likely dead though, so maybe it's best not to know).

On the other hand I understand many burned fans want to leave the reaper baggage and the ending disaster behind. Also, fleeing from the reapers on massive arks built by space magic within two years is ridiculous, especially if privately funded and secret.
The exploration spirit is easier to swallow. It still makes zero sense to me why anybody would pour so much money into so risky an endeavor when most of the Mikly Way is still unexplored. But bored people have done dumber things.

And I'm pretty sure there are a number of REALLY wealthy individuals who would have the kind of money to pull that off. So how this got funded is not an issue to me. The timeline is the problem.

So I'd prefer the reaper scenario from an emotional point of view but an exploration adventure (with a possible ulterior motive) years in the making sounds less jarring. So I guess that's the better choice...

Oh right, I forgot about that.
In that case... good for these foolish explorers!

Sane is a bit of a stretch. The plan to stop the Reapers was centered on the Crucible. Without, it was clear this cycle would be annihilated.

BW loves to overcorrect. Don't like the Mako, take it out. Inventory is a mess, take it out. Hate elevators, take them out. Don't like the ending to Mass Effect 3? Set the next game in a new galaxy. I like the idea of a "Mars Generation" type story and I think I could buy into it a lot more if I didn't know they did it to get around the endings. I know that's meta, but it just bugs me I guess. It's not a deal breaker, but it's more like Sole Survivor Shep working for Cerberus w/out mentioning a certain Thresher Maw incident. It's just sort of nagging and annoying because I know it's there, like a rock in your shoe.

So letting everyone die is a sane decision?

This, this, this. It's crazy they're still doing it considering how they should know by now that it hasn't really worked by and large. They bend over backwards to please fans WAY too much. When they her criticisms they shouldn't take it as "Oh, Linkenski hates this, let's address that by reworking that thing or remove it entirely" they should think "hm, that didn't work out as well as it should've, let's analyse what we've made and figure out how it can be done better or what changes we can make to improve the next game".

I'm sure they do consider things but so often lately I feel like they're taking the "it's good enough" approach, and part of that is in how they just take exactly what fans have whined about and change the disliked element so it's the 180 degree opposite of what it was before. The problem in DAII was just as much that environments were repeated too often, so in DA:I they created massive areas and even made sure main missions didn't repeat environments when they really needed to like at the start of In Your Heart Shall Burn because the transition from launching the mission to just standing atop the mountain below the Breach was super anti-climactic for such a big turning point in the narrative. That was exactly when we'd have needed to go up that mountain again and face even harder demons.