Finished my playthrough of the entire series (100% achievements). My (very long winded) impressions of Mass Effect 3 after nearly 10 years:
-I still think it's the best in the series. It starts much rougher than I remembered. The first 2-3 levels are very dull, and the game cuts a huge amount of corners in introducing things to the series to get things moving that could have been introduced more elegantly. There also isn't much to do in the first half of the game. However, it opens up considerably after the Genophage storyline is resolved, and the final half of the game still impresses me at how it is, at once, one of the most operatic and grand in scope games I've ever played, yet also how intimate the character stuff is at the same time. Honestly, I've never played any other game series where I was as emotionally invested in the plot and characters as this. The Witcher series definitely surpasses any of the Mass Effect games in terms of writing, plot, and characters, but God dammit, the Mass Effect series has such heart. I don't think I've ever gotten as attached to any of the characters in the Witcher games as I did to these characters. And the Witcher games just don't have the same sense of Scope and C&C paying off across the entire trilogy that the Mass Effect games have.
-The Citadel DLC almost singlehandedly saves the game. So much character stuff is packed into it, and I realized playing this time (for the 3rd time), that I missed a good deal of it during my first playthrough. There were whole character vignettes I somehow missed in previous playthroughs. It took me nearly 6 hours to complete the entire DLC, which is massive. The first time I played ME3, the Citadel DLC hadn't been released yet, and I can't imagine how empty the game would feel without it. All of the real character send-offs are in the Citadel DLC. In comparison, the awkward scenes where Shepard calls all his friends prior to the final assault seem kind of silly and anti-climactic after playing it.
-My view of the ending was much improved this time around, possibly just because I was paying closer attention to it than I have in the past. In replaying the series, I wanted to test a pet interpretation that I had of the Reapers, mainly that they only act like they do because, from the perspective of organics, they are really fucking stupid. The reapers are not a god-like intelligence, nor is the catalyst. They are just AI created by an ancient, inhuman, and somewhat inscrutable race that was given the directive of protecting organic life from synthetic life, and they eventually evolved the cycle of Reaping as a means of ensuring that organic life survives (their logic being, in its simplest form: 1. Organics will always create synthetics, 2. Organics are imperfect, so conflict will always result from this, 3. Synthetics will eventually reach such an advanced state that they will inevitably destroy organics, so 4. as a solution the Reapers decide to harvest and assimilate Organic/Synthetic life that reaches an advanced state of development, ensuring that Organic life will continue). Admittedly, Isaac Asimov this ain't, lol. I don't think all of these premises make total sense, nor does one necessarily logically follow from the previous (the biggest problem being number 2, which I don't think is self-evident or a necessary outcome). However, I think the series does all of the required hand-waving needed to make it plausible. You can forgive a great deal about the Reapers if you keep in mind that: (1) the species that created them is wholely alien (and thus their motives may be difficult comprehend) and (2) the Reapers themselves turn out to be fairly rudimentary AI simply working through their code (in fact, while it's never stated explicitly, I actually think it's arguable that, in terms of AI, the Reapers aren't as advanced as EDI or arguably even the Geth. The reapers are just mindless machines carrying out their ancient objective. They really don't seem to have evolved beyond that, and there's a level of absurdity in the scene where you finally discover their motives that I personally found amusing, but many other players seemed disappointed by. It's like finding out God is just a clockwork mechanism, lol).
Is the explanation for the Reapers' motives perfect? Hell no. It's very clear that Bioware was making this series up as they went along, and I think the overall arc, especially, suffers at times because of it. However, I think the place that they arrived at regarding the reapers' motives was fine, in the end, and nowhere the abortion that many hyperbolic fans make it out to be, especially given that.........
-THE REAPERS ARE JUST A MACGUFFIN! Replaying these games has convinced me of this more than ever. 99.5% of Mass Effect 3 involved tying up all of the character and species plot arcs set up in the previous games. About 5% of the game's running time was spent on the reapers, who really don't matter in the end. The reapers aren't even the games' real villain. The villain turns out to be the Illusive Man, and he's actually an awesome villain (he's nuanced, has motives that are intended to do good, but he's corrupted in pursuing them, and you can actually get him to see the error of his ways in the end, which is refreshing). The Mass Effect series is about its characters and species. The reapers are just a motivating device to give Shepard the incentive to go on a picaresque journey where he meets lots of aliens and helps solve their problems. That is the heart of these games and what makes them work, not the central reaper plot.
-To critique the games a bit, the renegade/paragon system is really outdated, and I think Shepard, as a character, suffers considerably because of it. Honestly, I don't really like Shepard. Paragon Shepard is fucking dull as dishwater, while Renegade Shepard is a massive prick. Toward the end of the games, I kind of started to wonder why everyone loves Shepard so much, as he's really bland person. I think it works well enough for these games, as the focus isn't on the main character, but as much as I was ambivelant about Mass Effect Andromeda, I think the smartest change it made to the series' mechanics was having the leads be slightly more defined, as characters, than Shepard was, who ends up being kind of a cypher in the end.