There are a lot of interesting ideas for variations of rules. Some ideas are presented (often with good argument) as changes that might amount to objective improvement in game play (reducing "luck" factors, hampering unsportsmanlike collusion, etc). For instance, pure "king-capture" play (no checks/check-mates/stalemates - people are eliminated as their king is captured) has been proposed as an idea to simplify player-elimination rules; and "points-for-uncaptured-pieces" variants might make for more balanced scoring. Other ideas are presented as changes that might entirely change the flavor of the game (random point-values is one such enticing idea; or perhaps a "Blitz" variation that removes the 15-second timer; etc).
Unfortunately, there's no way for many of these discussions to go beyond speculation over the pros/cons such variations would entail. Unless/until a particular variation is deemed "worthy" of being unleashed upon all players by the chess.com "Overlords", there's simply no way to establish an empirical case (eg. example games) that one variation is truly worth broader consideration.
I'd previously proposed some sort of "experimental release" approach, where one-off variations of the game could be published "off-the-menu"; available for small-scale testing/feedback, but not distracting from the progress of the major release path.
After giving this some more thought, I realized there might be a cleaner way. What if certain "intriguing" or otherwise-promising rule variations were offered as options in the pre-game screen (before clicking "Play")?
The main hurdle is the logistics of "matchability"... even with just 3 variations, the chances of 4 players all selecting the same variation within a reasonable window of time is probably next to nil. What I'd propose is a list of all available rule variations (including "Standard Play" variation), wherein players are allowed to select one setting for each variation:
* "Yes please!" (I prefer this variation)
* "Meh" (I'm okay with this variation)
* "No thanks": (I do not want to play this variation)
By default, "Standard play" is marked "Yes please!", and all others are marked "No thanks" (this would guarantee that any player who does not modify these defaults will get "Standard Play"). Furthermore, "Standard Play" only allows "Yes Please!" and "Meh" (it is not possible to choose "No Thanks" for "Standard Play")
Opponent selection would be completely independent of these preferences; in other words, 4 competing players are chosen using the existing player-selection algorithm. Thus, this new feature will in no way introduce delays in games getting started. Once 4 players are brought together to play (again, using standard rankings-based player-matching algorithm), their preferences are scanned. The variation to be used for any given game is decided as follows:
"No Thanks" acts as a "Veto". No player will ever be put in a game variation they have vetoed.
Of all non-vetoed options, "Meh" counts as a +0 vote and "Yes Please" as +1. Whichever of the non-vetoed variations has the most "Yes Please" votes from the 4 players is used (random selection is used to break ties).
Lastly - whenever a non-standard variation is used, at the end of the game, all 4 players are asked to rate "How much did you enjoy this variation?" on a scale of 0..5. Those variations that consistently rank near 5 - perhaps they are considered for incorporation into standard play. Those that consistently rank near 0 can be quickly pruned out of existence.