There is a common problem when it comes to rating - that it often does not accurately reflect how good of a player someone is. While one could discuss the advantages/disadvantages of using our rating system, I'll focus on an issue more unique to FAF - that is, players who only play a single map or type of map tend to get good at that map and nothing else.
There are definitely some egregious offenders in both maps and players, and solutions like making certain maps unrated have been suggested. I however, have a better solution.
FAF would keep track of the list of your recently played maps. If FAF notices that say, you have played the last 6 or 7/10 games on a single map, it will reduce the amount of rating gained from winning a match on said map. There should always be a reward for winning a match, but this would prevent people from boosting their rating by going back to certain maps after a loss.
In terms of mapgen, something similar might be implemented. Maps generated with the same presets could have wins penalized in the same way. (I don't know if this is possible - whether any info about a map can be gained from it after it's generated - perhaps indicators can be written into the map files if they're not already there).
