It seems as if there are 2 main arguments for keeping 6 player SG starts and raising it to 12.
For one, 6 player SG's make it so that it is much easier to get into games to play, that's something we all want, and for people who play late at night on some of the other servers that don't get filled as much, it's hard to find big servers.
For the people arguing on 12 people servers, they find it that people can be easily called out for "abusing wins", "boosting", and other things. It also takes away from the "Survival Games Feel". It's not like you start out with very few people, no, it's a bloodbath in the beginning then you try to hold your own to the end. Obviously that "Feel" is going to change, but 6 player servers don't support any "Feel".
I'm on board with the 12 person games, first, it can make rules and restrictions on teaming, much more simple, it would clean the community's attitude at people "boosting". And you may say: "Well it'll be impossible to find a game!"
6 player servers separate players and take some time to find a server, try to congregate to one server, it's not that hard.
TL;DR: I agree with the 12-person-minimum idea.