Implement a ratings system on servers (perhaps Glicko-2)
Give players a Glicko-2 rating and rating deviation, updated based on Trosnoth matches they play on the server (not variety games).
Why it would be valuable
This could provide extra motivation for people to come back to the server, especially if the ladder of active players is shown on an end screen after each game.
It could also be used to work out automated match-ups for casual games on the server, including with bots.
Each player would be given a Glicko-2 rating (or other ELO-like rating). When Trosnoth matches are played on the server, player ratings would be updated.
If Glicko-2 is used, we might use an update period of, say, one week. When a game is played, a notional rating change would be made (to give the player immediate feedback), but the server would also store the ratings as they were at the start of the week, and at the end of each week, the proper update algorithm could be applied.
We would need to come up with a model for working out the probability of a win based on individual scores in game with multiple players per team.
The server web interface should then prominently show a list of players that have been active this month, along with their current rating. For Glicko-2, we might just display the lower bound of the 95% confidence interval (rating - 2 deviations), so that players can improve their rating by decreasing their rating deviation (by playing more).
This list of active players and ratings could also be displayed in the Trosnoth client, at the end of each Trosnoth match.
The list might also include certain bots at certain difficulty levels (probably RangerBot and AlphaBot, each at all three difficulty levels). We should probably provide some default starting values for the ratings of these bots (perhaps based on a simulated bot tournament), but the bot ratings should be updated when they play in games.
The ratings could be used to work out automated match-ups on the server. When only one human player is on the server, they can be paired with whichever bot is closest in rating to that player. This pairing could be used in a 1v1 game, or it could be used in a 2v2 game with a random other bot placed on both teams. If two players are active on the server, they could be placed in a mixture of 1v1 games against each other, and 2v2 games either against each other plus a bot (selected based on ratings), or humans vs machines, with the bots chosen based on ratings.