If I may give my two cents here, I grudgingly understand why Circuit should go (even though it means one less division to have fun with), but at the same time I think it should come back once the gametype itself has been cleaned up. The whole concept of Circuit is a mess right now, which is a large part of why bad Circuit maps break the gametype in a way that bad Match and bad CTF maps don't.
Having lives, for instance, is a terrible idea...as I understand it, this has already been fixed for the next version. Also, people who belatedly join a circuit round should exist as spectators only, so that they won't be on their first lap while everyone else is coming in for the big finish. For that matter, I don't even think we should allow the person in last place to complete the race.
I think it's more that bad circuit maps tend to immediately end up unplayable, while bad match and ctf maps just end up mediocre and boring, and sometimes even end up oddly compelling because they're flawed in a manner that actually makes them interesting to play even though they suck.
I understand where you're coming from on this, but I think you may be exaggerating a tad. Match may be pretty stable in this regard, but we've seen more than our fair share of CTF maps that totally break the game (Canyon CTF, Castle CTF) as well as some CTF maps that actually look decent but are still broken (Misty Mire). Come to that, there are nearly as many Single Player levels as Circuit levels which are broken beyond salvation (White Mountain, much of A Cat's old work). At the same time, we've seen plenty of badass Circuit maps (Thunder Factory, to name the most obvious example, and Lost Feelings Island), and plenty of bad Circuit maps which are still perfectly playable.
My biggest fear is that by dropping Circuit entirely from the OLDC, we'll discourage people with actual talent from working on such maps. When was the last time someone with a single straight-up level dumped it in Releases instead of submitting it to the contest? It happens, but it's pretty rare. I can certainly attest that without the contest format as a showcase, I wouldn't have bothered to make Wacky Tesseract or Girder Detour in the first place.