IMO there shouldn't be any medals for individual maps, just a little mention.
There should be seasons, for example 1 season is 12 challanges, and after that the winners of season. So then I see the sense of keeping points for activity, you can still report your time, but you won't get any extra points for expired challanges.
And there still can be overall rating too
what do you think about my idea?
Anyway in a month I'm starting to study, so I guess I will not have much time for playing, we will see