The text in each player's rating/profile boxes could be links to the appropriate leaderboard (Assuming you're not actively playing in a game).
Variants Server Suggestions [Post-4PC Merge]

The history of players' ratings could be tracked. There could be a panel within the archive to display that information in a graphical format.

There could be a switch to hide all deal offers. I don't know about everyone else, but seeing someone spam the button every turn gets to be pretty distracting. I also propose that the default position for this switch would be customisable in players' settings menus.

En Passant captures should only count for one point, even if the pawn was promoted. I suggested this ages ago, and as I recall, the response was "yeah, makes sense, but not widely applicable." The sheer popularity of War for Throne nowadays suggests a revisit would be appropriate.

Eggshell Chess variant. Suggested long ago, looked into, then seemingly abandoned by the devs. For more info, please read my original post.

Fewer listed variants - From my time as a CGA, I remember having this debate with numerous people, and most of the time, we decided a smaller selection pool would result in the increased popularity overall. Now that the list has been pruned some, let's keep that trend going.

Give players the option to hide their arrows from spectators. There are some players out there paranoid that their opponents will use another account on a separate network to observe and relay their plans by virtue of reading their arrows. It would be convenient to give these players the option of hiding their own arrows from spectators.

Give players the option to disable chat in all games, as a default setting. This is an option on chess.com/play, so why not do the same here? Anyone can use /stop-chat, so why not just allow players to do it automatically through a setting? I can see how this could be frustrating to some, so I think in 4-player games, it would only be enacted if 2 or more players had the setting enabled.

Going along with the idea of rating history, show an indication of recent rating net change next to each rating, or within the hover text. I would suggest showing the past 5 games' worth of rating change, or change over the past 2 weeks, whichever is shortest.

Spectators of anonymous games should be anonymous to the players. In games with smaller player pools, it can be an advantage to know that a certain player isn't in the game. If that player appears in the spectator list, that information can be useful.

We only have 1 developer. I have essentially retired from coding, 5 years of full steam are enough. We'll need volunteers, or some of these things may never happen. Next bigger addition will be piece banks and drop support for stuff like Crazyhouse, Setup chess (automate style), or Seirawan chess. (The boss of bosses here loved automate and wishes setup chess asap)
Here's my personal view:
- Links to leaderboards from profile boxes
yes will do - Rating history archive
kindof a lot of work, need volunteer (and I still believe you could do it yourself if you wanted to, very much your cup of tea. It's not that much different from doing it in Excel..) - "Hide deal offers" toggle switch
convince @GDII to add it - En Passant = 1 pt.
personally disagree. If you don't want to give away points, then dont promote. To me it makes no sense that capturing a piece should not give full value.) - Eggshell Chess Variant
Sounds very fun. But, a ton of work, would need a volunteer (a real coder, this isn't Excel). Not an easy task. - Fewer listed variants
Agree. Point here is that CGAs can list variants without a category (Most Popular, Extra, ...). They will be searchable via text search below the categories! and will show in the custom rule presets and in edit position. As far as I'm concerned, CGAs can list as many games as they like this way. We just don't want to overload the 'main menu'. Needs discussion with @bsrti and @qilp (worthy of own topic) - "Hide arrows from spectators" option
Personally not a big fan, ask @BabYagun/GDII. People are quite paranoid, and there are also already some measures in place to hinder multiaccounters from seeing arrows (or opponent's pieces in fog of war) - Disable chat by default
personally, don't like encouraging disabling chat for no reason. I view the stop-chat command as a necessary evil. convince bab/gdii - Recent rating change indicators
sounds like lota work, doesnt seem worth it (unless volunteer of course) - Anonymous spectators in anonymous games
really? yall don't love to see who's watching your game? dont like this cause it takes away too much fun/social, for not enough in return. convince bab/gdii

- Anonymous spectators in anonymous games
really? yall don't love to see who's watching your game? dont like this cause it takes away too much fun/social, for not enough in return. convince bab/gdii
It's fine if the game isn't anonymous. But imagine playing WFT when only about 5-6 full-time WFTers are online in an anonymous game. I know I can beat 4 of them with everyday tactics, and the other two require special attention. If I see their names in the spectator list, that's a non-negligible advantage for me.
Also, side note: Thank you for your detailed responses! I know you're probably due for some time off, R&R and such, so these are mostly aimed at the other coders who are now eager to start improving the game and adding new features instead of just porting an old system into an new interface.

I fully understand your reasoning, I just think it's too big a sacrifice to add it as a general rule, to only cover one rather rare/specific case. It would need to be more specific, aka "only when top rated game with small player pool", which is kinda hard to code..

I think that there should be an option for how many games people have played to be able to join the game, similar to how you can make restrictions for rating. [...] You could be 2000 but only have played like 25-ish lucky games, or you could be 1800 but be a much better player, having played more games and understanding the game, rather than just farming noobs who also have no idea what they are doing.
(copied from this separate thread)

I also have a suggestion. I’ll just post the link to the thread I made over in 4PC.
https://www.chess.com/clubs/forum/view/suggestion-change-in-terminology
The tl;dr is that 4PC games should have 4PC in the name and as an icon, when viewing it in the variants lounge. I posted a little mock-up for the idea.

4PC games should have 4PC in the name and as an icon, when viewing it in the variants lounge.
In favour of the icon. Adding "4P" or "4PC" seems like clutter in my opinion. All games with "FFA" or "Teams" in their titles are 4-player (except for 3-player games, which can also list as "FFA" -- but there are few, if any, of those).

If there is a lone points leader in any game, he should automatically accept any deal offers, similar to autoclaims and autoresigns. The only reason I can think of why the leader of a game wouldn't want to accept a deal offer is that he's purposefully arranging the scores so that a certain other player can come in a higher or lower pole position (i.e. kingmaking). But the same reasoning could be an argument against autoresigns, which, to my knowledge at least, still exist.
I guess it could also be said that there's not really a reason to add this because point leaders could just hit the "deal" button if they see it offered. But, in faster time controls, this may be a time-wasting decision to contemplate. I know I've been saved in many a hyperbullet game by autoclaim when my opponents had more time that I did.
Last note with this: It would be best for this feature to override the proposed "hide deal offers" toggle switch.
EDIT: I just realised an unintended consequence of this: Players in 3rd or 4th could, in essence, claim 2nd place. Let's say the scores of a 20-point-mate game are A: 65, B(dead): 56, C: 47, D(dead): 23. Player C sends a deal request, and A auto-accepts, since he's in the lead. Boom, A and C are each awarded 10 points, putting C ahead of B in the end-of-game standings. That seems antithetical to the game. I withdraw this suggestion.

Based off this comment in the 4PC Club:
Far fetched idea. but some of the sentiment towards the merge is coming from what I would call the "/variants design", how "hard it is to navigate" and that sort.
Maybe a toggle to switch back to the old design, while still being on the same server? Or an alternate sister server, that connects with chess.com/variants to create a network?
Well, it's been a few days since the big 'ol merge between chess.com/variants and chess.com/4-player-chess. It seems like the coders/devs are busy running around patching bugs, updating things (a million thanks!), and just putting out fires in general, so I don't expect any of this to be listened to that carefully any time soon, but I thought I'd start a conversation, and place for general suggestions to be posted. I have a few of my own, which I'll plop down in the comments, but others are welcome to contribute as well, so long as A) You're actually making an earnest suggestion of something you think would be to the benefit of the playerbase at large, and B) You're not suggesting a reversal of any changes which were made with the update. We get it, you don't like change. Go home and cry to someone else. I'm hereby giving (and requesting) for the forum admins to remove comments which don't adhere to those two criteria.
That being said, I'll try to keep this list updated, based on what's been suggested. I'll also mark the list with the following icons:
So here's the list (will be updated with my own, and others' suggestions from the comments):