The defaults on the Forgable maps are supposed to suck. That way they encourage creativity for other people to create their own maps to what they thing is better.
But like I said, if that's true, then why is it still shoved in our face on a par with proper maps in MM? I love Team Mythic but Default Sandbox is something I'm less than keen on seeing on a regular basis, which is how it stands.
All I have to say about this is that Bungie is a very unaccepting company: There has been the Conquest petition, Lower the Guns action, and I'm guessing a petition about getting a Community playlist. None have worked, so either deal with the default which sucks and the variations which suck even more, or play 7 on the 7th only and play Customs.