Thanks for being diligent. I've listed some suggestions and issues below, mostly related to UI and workflows. I'll gladly attach videos upon request for any of the relevant suggestions below. Feel free to DM me for further information as well.
1. Voice chat is enabled for matched players before a game begins, but there is no ability to mute said players. Either please disable voice-chat until the game begins or enable muting during this period.
2. The 1v1 variant includes the Onslaught map, which is a team-oriented map that uses team-oriented spawns. Given this, players can anticipate the base spawns and break the balance of the game by shooting before the player as they spawn into the game. Please remove that map from the rotation given the weakness of its spawn placements.
3. Action Sack is tons of fun, god bless. Maybe add in some fiesta variants too, please?
4. Why create an "idle" state for players in matchmaking lobbies without a UI element/alert to make it clear that they're idle?
5. Thanks for putting in big team heavy variants!
6. Please remove all of the flood-themed imagery... the initial loading screen is just... is just an overlay on the pre-existing one... and the menu screen is pretty bad, too. Even though the flood are an integral part of the Halo universe, looking at flood goop doesn't evoke the right feelings. Have a marketing-minded person choose these photos. A menu for a game should sell the fun that the player is about to have, and showing off the thing that Halo players often gripe about (don't get me started on ANY of the flood-focused campaign missions: the library, cortana, etc), is neither good for the returning veteran nor the excited newcomer. Have a slideshow of campaign highlights and action-packed multiplayer screenshots. Replace the boring, sleep-inducing background music with something upbeat as well. There's plenty of examples, and you can cycle through them if you're feeling frisky. (One Final Effort: H3, Delta Halo Suite: H2, Covenant Dance: H1.) I also don't understand why certain UI states during matchmaking alter the volume levels of the background music. Just fade it out before the map loading happens?
7. Using the bumpers to switch between players in the post-game carnage report will of course prompt for a data-refresh for the game stats, but time and time again, the current highest rank fails to update for that player. I've noticed progress in this area: it used to be broken entirely and would only show a loading spinner, but the system still consistently fails, usually showing a different player's highest rank.
8. I'd love to know how I've unlocked certain player ID items. The unlock instructions are available for locked items, but not every item is listed. For example, the beamish and mister chief avatars are hidden and their unlock tip is not visible. I have friends that have these but they sadly cannot tell me how they're unlocked. I can of course use google, and I have, but I find it rather frustrating (and anticipate the same from new players) that the unlock tip goes away once the item has been unlocked.
9. The multiplayer menu screen has scroll sound effects for left and right movement even though vertical movement is only available. There's also still the bug where you can equip emblems that you've not unlocked by just hovering over the emblem and waiting for a matchmaking match to begin, thereby kicking out of the menus. I've been using emblems I've never unlocked literally for years now.
10. Scroll sound effects do not work with the Play button in the social games composer. Entering or leaving the play button does not provide sounds, and entering the games included area from the game size toggle does not include the scroll sound effect either, thereby creating a bit of dissonance when the user is operating the menu.
11. I'm going to gripe about some of the UI screenshot imagery. It's a bit nit-picky, but alas, it is something that doesn't really make sense. So: why does the H3 Team Arena playlist image feature a spartan with non-team colors holding a spartan laser on Assembly, a map that does not feature a spartan laser? Please choose an image that is actually from team arena...
12. Please try to list the map name on the map loading screen for maps that have varied variants, aka Foundry and Sandbox.
13. The H3 Hardcore team doubles also features a spartan with a sword on Narrows. There's no sword on Narrows, fam.
14. While we're being sticklers you might as well change the image for the HCE Team doubles to show a blue or red Spartan.
15. The H3 Lone Wolves playlist image is on Longshore, which isn't even a map in that playlist's rotation.
16. The multiplayer menu (where social, competitive, custom, etc options are list) has a social games image from what looks like Halo 4 Spartan Ops or Halo 4 campaign cut scene? Pretty sure that's not a social game.
17. Likewise, the competitive games image on that same menu shows Halo 4, which isn't (currently) an available game in any of the competitive playlists. (lol, and let's keep it that way.) All I'm asking if for the images for these UI elements to actually correspond to the label. It's almost like the people designing the UI haven't even played the games. Also worth mentioning that the text "Join thousands of other Spartans ..." for the social and competitive games options says "spanning all Halo games" which is, uh, which isn't correct. Similar phrasing is also used elsewhere.
18. When a teammate quits the game that is not part of your party you should not be penalized for also quitting the game. This is implemented in ranked rocket league, btw.
19. Matchmaking "top medals" shouldn't choose medals based on how many you have of that medal, it should show your "best" medals, like overkills, perfections, running riots, flag caps, etc. Seeing everyone top medals, aka headshots and beatdowns is repetitive and uninteresting. As for how to implement this, instead of hard-coding a value-based system to compare medal "quality", how about you just run a script that computes the rarity of the medal based on total player matchmaking statistics?
20. Add some of the lesser-known gametypes at some point like VIP, or juggernaut.
21. Lone wolves seems to feature a disproportionate amount of king of the hill. Check some logs to determine if this is true.
22. If you are not the party leader in matchmaking and your host returns your party to the lobby, you cannot view the post game carnage report until you queue up for another game. This does not happen for the party leader.