While I suspect the ending of ME3 is going to remain the same in the remaster, I do think (hope) there's the possibility that it might allow for saves to be transferred over into what's looking like it's really, actually, finally, going to be "Mass Effect 4."
If it did end up changing the ending to undo what ME3 did and lead into this game though, I'd be 100% for it. And I won't lie, the thought did cross my mind as to that maybe having something to do with Casey Hudson's departure too (though the Dragon Age lead going at the same time makes me think it's more likely an "EA/working conditions" thing, but I guess we'll probably never know).
I bought the DLC for Mass Effect 3 years ago when it went on sale, but could never bring myself to actually go back to it after that ending. Then last month, in the run-up to the PS5's release and needing to move a console to make room, I finally got round to playing them. This was before the remaster was officially confirmed (even though we all knew it was coming), before the concept art and confirmation of a new game. And after playing those DLC's (especially Citadel) and remembering just how great those characters were, how great that universe was, how good that writing could be (at its best), and just considering where Bioware and the Mass Effect series were both at right now, I felt like the absolute best possible thing they could do would be what it looks like they might actually, really be doing.
The truth is that the Bioware name has taken a hit in recent years, and so has Mass Effect's. With regards to the former, Dragon Age 2 was the start of it, but they were still riding high. Then Mass Effect 3's ending happened and that was a disaster. That was where things really started to go downhill for them. Then a few years later both Andromeda and Anthem proved to be huge duds, with Dragon Age Inquisition being the only thing they've put out at all recently that wasn't torn to shreds.
At this point Bioware can't just rely on brand names, either theirs or Mass Effect's, to get people excited in the same way that they used to. If Andromeda had been a hit they could maybe have done a follow-up, or had another new, unrelated Mass Effect game that people could have been excited for because they'd still have been riding high on that series. But at this point, if they'd announced a "new, unrelated Mass Effect", that just wouldn't have cut it. People just wouldn't have been excited about that anymore.
So what's the one thing they would be excited about? The one thing they now are excited about? The one thing that they'd be hopeful for, even knowing the Bioware of today may no longer be the Bioware of yester-year? Bringing back the old squad mates. Going back to the Milky Way post-ME3. Potentially undoing that ending. And bringing back Shepard.
Whether or not that's what's actually what's going to happen we don't yet know, but that trailer damn sure as hell made out like it was, and that alone is enough to get more more excited and hopeful about Mass Effect than I have been in over 8 years.
Certainly as with anything, there are many ways it could still turn out to be a disappointment. There are theories going around that it might be set hundreds of years after ME3 with Liara being the only returning squad mate, based on how long asari usually live for, with everyone else bar maybe Grunt potentially being dead and gone. And if that's the case then I'd wonder why they were even bothering with all this, going back to a post-ME3 timeline, teasing an original, returning squad mate etc. in the first place.
But that trailer gave me hope. It gave me something I'd always hoped for but never thought we'd ever actually see. So right now I'm going to sure as hell roll with that and hope that this game is going to do what this trailer implies it is; the return of familiar faces, old friends, and the next Mass Effect game I've been hoping against hope for since the end of 3.