Oh yeah I definitely agree with the too much manual work point. There are a ton of games that full under this distinction and I imagine it would be hell for those attempting to do it. That said, I feel like there is definitely a big distinction between spam games and shorter/smaller games, but I understand why some cases may potentially be a bit indecisive.In my opinion, that would be too much manual work, instead of working on tracker features. And it would get too subjective/personal. How would Exophase separate "spam games" from easy, indie or short games? Every gamer has his own perception of what that would be. And it exists on all platforms, not just Steam.
Edit: And you can still get the top place, by playing games with rare achievements. Easy games are barely worth EXP now compared to how much it used to be in the past.