Perhaps that impression is heightened by the frequency with which they turn up in Forum Spy?
I'm not involved with any of these games, so I don't have a stake in them at all. Secondly, I'm sure the original people who kicked this idea off over here have an understanding of sorts with staff to ensure that they don't become a nuisance and are wastelanded after they're done so that they don't become spam holes. Just glancing at the community page, I see four threads on the first page, hardly 'littered full'.
I think they're a great idea for bringing people together, perhaps introducing new forum members to long-term members, and for giving people just one more reason to stick around over and above everything that goes on around here. One of MacRumors' strengths, in my mind, is the community aspect of the site, where there's more going on than just the core news and technical forums, something I feel has become slightly diluted with the reorganisation. The more variety and interest that the site has is a strength, in my view.
However, I occasionally do wonder whether the frequency of them can lead to some becoming a bit jaded with them, seeing as there's at least two flavours of game from what I can tell: the ever-changing pro's edition for those who know the game inside out and a simpler version for those who might want to try it for the first time. It also seems that a new one kicks off the minute an old one finishes, so a possible suggestion is to maybe restrict them to once per month for both kinds, maybe kicking off on the first of each month? This would ensure that they continue, but giving the forum members who object to them a break as well, giving those who participate something to look forward to.
My other thought about the pro's version of the games is that it seems, from the outside at least, that they're becoming increasingly esoteric and complex with discussions about rule changes and the like, condensing the core participants down to a group that seems relatively static in its makeup, which seems slightly, but not deliberately exclusionary. One of the things that can turn people off is endless discussion about process, so I'm wondering whether rules discussions could take place offboard by PM or email amongst the circle who are most invested in them, so that when a new game starts, the rules are there from the get-go.
Like I said, I don't play them, but they don't bother me either, but they do clearly bother some... they have a valuable role of sorts to play if managed correctly, so squaring that circle might just be a matter of having fewer of them throughout a 6-12 month period and organising them slightly differently, ensuring they're still fun, but maybe a bit more rare and therefore a bit more special.