I'm going to post my rambling, semi-organized thoughts on our roster.
The first half or so of our base roster was pretty predictable, though that feels like a given - there are a LOT of characters to cover for both Marvel and DC, and by extension, a lot of fan favourites that people would want to see making it in. I probably could have included more characters by default, rather than having people vote them in; at one point, my plan was to have 5 characters per side by default, with Batman, Superman, Wonder Woman, the Flash, and Green Lantern for DC, and Spider-Man, Wolverine, Iron Man, Captain America, and the Hulk for Marvel. However, I wasn't sure whether people would prefer Barry Allen or Wally West for the Flash, or Hal Jordan or John Stewart for Green Lantern.
Up until the non-Injustice/non-MvC rounds, the only things that surprised me were that Dr. Doom didn't come in first for the Marvel villains round, that Raven was the most popular Teen Titan by far, even beating out Nightwing. (I didn't see much of the Teen Titans cartoon, so I was unaware of her popularity), and that Cyclops beat out Storm in the X-Men round. (I wouldn't change any of those outcomes, though - I'm still getting caught up on X-Men, but Cyclops seems like a character that's underrated by the fandom at large, and while it took longer than I expected for Cyborg to be added, he did eventually make it into the base game)
The non-Injustice and non-MvC rounds are where this thread really started to pick up steam, to the point where I bumped up the roster from 48 to 50 due to the sheer amount of characters that were nominated for the non-Marvel vs. Capcom round in particular. I'm really glad that we got the Thing and Ms. Marvel in this roster, and while I'm not as passionate about Daredevil as I am when it comes to the other two, he's a great addition who really should be in a fighting game by this point. (plus, with the benefit of hindsight, he's in the same roster as the Teenage Mutant Ninja Turtles, who were directly inspired by him)
I don't know much about Plastic Man or Constantine, but I was glad to see them make it in, and these two rounds are where we started to shift away from just using Injustice and Marvel vs. Capcom characters. (though don't get me wrong - we still added plenty of those) The inclusion of Ra's al Ghul and Doctor Octopus showed that I wouldn't have to include another non-Injustice/MvC round to force the issue, and that they'd be added naturally.
As a side note, I'm glad that we got Zatanna in this roster after she was left out of Injustice 2. I haven't read much of her in the comics yet, but she seems like a fun character. Martian Manhunter and Green Arrow felt like missing pieces that were put into place - two core Justice League members who finally got into the roster. Plus, it gave me an excuse to post this!
This was also the point where Thanos and Darkseid were added in by default, leading to our base roster reaching its final total of 52. I'm glad that they both got in, rather than having to wait through the cosmic rounds and other rounds where they'd be eligible, hoping that enough people would vote for them or else we'd have a "Sigma in Marvel vs. Capcom Infinite" situation on our hands.
Loki felt like a character who needed to be here, given how much his popularity EXPLODED since Marvel vs. Capcom 3. Speaking of villains from the first appearance of a super-team, I'm thrilled that Starro the Conqueror actually made it into the roster; I wanted to get someone unusual or unexpected in here.
When it came to 2000s characters, Blue Beetle (Jaime) and Ultimate Spider-Man (Miles) seemed like the best picks. I'm not very familiar with modern DC, but Blue Beetle seems to stand out among the company's recent creations, and it's a tough call between Miles and Ms. Marvel/Kamala as to who Marvel's biggest hit of the past decade or two is.
As I said earlier, Cyborg felt long overdue, and I was so glad to see the Wasp making it in after she had been relatively neglected when compared to other long-time Avengers. (likely because she wasn't in the Avengers movie)
If I had to pick four DC characters where I felt that they could have been in the base game (to round it out to 30 each), I'd go with Black Adam, Mister Miracle (I wanted to see a New God aside from Darkseid in the game, to show that there's more to the property than just him), Gorilla Grodd (the lack of a Flash villain stuck out to me), and Poison Ivy (or at least one of the more sci-fi themed Bat-villains), so all of them making it in through DLC was great. I do feel like we could have used a wider variety of villains, but I'm only kind of familiar with Wonder Woman's, Green Lantern's, or Aquaman's rogues gallery, so I'm not sure who I'd go with.
I'll be honest, I don't get the appeal of Gambit, but I'm happy for those who do. I was glad to see Squirrel Girl and Hawkeye make it in; I'm surprised that Clint Barton wasn't nominated for several later categories that he'd be eligible for, but maybe people don't like doubling up on characters with the same identity. Or maybe it would lead to this kind of situation:
I don't know much about the Sentry (and I know that under the pen of some writers, he can come across as a God Mode Sue), but 1SecondNinja's moveset definitely opened my eyes to his potential. Ultron felt long overdue, and while I'm aware that she's a controversial pick, I love that we got to include Lois Lane on the roster.
I'm a bit more neutral on season 3 - I'm aware of the Marvel and DC characters that we included, but I don't know much about them. (I've watched Peacemaker and Moon Knight's shows, but by my understanding, they're very different in the shows compared to how they are in the comics) They all make sense to me, but I don't know a ton about many of them. (basically, the characters make sense, but I don't know enough about their series to be super-hyped - kind of like Simon Belmont in Smash, at least for me) Magik and Booster Gold were great inclusions in my eyes, and I'm happy with any outcome of this ongoing poll.
As for the guest characters, I'm only vaguely familiar with Spawn, and I've only watched one episode of Invincible, but I'm glad that we got all of them! I feel like, if this thread was happening anywhere other than SmashBoards, Scott Pilgrim might not have made it into the roster, but his comics (and movie) clearly resonated with a lot of Nintendo fans. I've been reading One Piece for 16 years now, and watching Dragon Ball since I was a kid, so having both of them in this roster is amazing for me. (and it goes without saying that I'm thrilled to have the Teenage Mutant Ninja Turtles in here - I nominated them twice and quoted as much of the theme song as I could in my nomination)
All in all, I don't have any complaints about the roster that we got. There are some characters that I don't know much about (mainly on the DC side, though that's mostly due to me not having access to those comics until recently), but there aren't any cases where I'm not sure why the character got in or cases where I'd replace them with someone else.
(there are a lot of Marvel characters that I'd like to see make it in - the Vision, Hank Pym, Namor, Kang the Conqueror, America Chavez, any of the top three from this round, etc. - but while I could add another season of DLC, I feel like we could probably keep going on for another 50 characters per side and still leave out some great ideas, so I figure it's best to try and stick to a limit. Unless we get a tie for first in this vote as well)