I've been reading this thread and thinking. So far I notice mainly these problems:
1. People add up as captain just to play(even newer people)
2. People who have lots of experience play captain and choose their friends, usually making it a roll.
3. People scrambling till they get their friends
4. People are offclassing full-time and not taking the game seriously.
5. People are not reporting to admins
6. Lack of admins?
7. People coming on alt accounts?(Making it 9v6 also?)
8. People using joke weapons?
There are problems that can possible conflict each other and aren't easy to solve. Number 1 2, and 3 for example, how can we stop that? One way is probably reporting to admin about it most definitely. This will help solve 4 problems. But we also have to think, what IS tf2mix for? I always thought it was not only a place where people can finally get picked who USUALLY NEVER GET to play, but a place for new players also, Newbie Mixes is another place, but tf2mix should definitely be one too. As for people not reporting to admins, I think when a player first enters the IRC channel, it should pop up something like"Need an admin? type !admin". So more people and newer players are aware of this function and able to use it when needed.
The lack of admins can definitely be a problem, but there seems to be many players in this thread that are capable, go pick them up! As for people coming on alts, that seems like a weird problem. In order for that to happen, one would have to give the password to their friends. I don't think it seems easy to catch who would do it, but should be reported anyway. Also possibly check if these people are friends with the alts/etc. The best you can do it leave it to an admin.
People using joke weapons, like I said earlier, hoping that tf2mix can definitely be a trustworthy place where new players can learn and get better, it'd be best to get rid of some unlocks. Not ALL of them, but to an extent where you can still use Gunboats, Kritz, Pain Train, and etc. They should only be allowed to use not only the default RL but also the Original and Direct Hit(could be talked about) more instead of some Beggar's Bazooka or Liberty Launcher.
In the end, there will be many players that will be a douchebag, asshole, whatever you want to call them. The newer generations have been infected by the bad generations of before. It's spreading more and more and people think their circlejerks are good or some shit. The only way to stop this cancer is definitely using admin when you get the chance. So people learn that it's NOT ACCEPTABLE.
I went into a tf2mix once, some brought their friends to spectate and just shit talk my team and etc. As there was also people who were very rude in general, and I was told by a friend that "TF2mix is a great and nice place for newer people". It shames me when I tell other newer to comp friends about tf2mix and they come back telling me it was shit. Let the people who are truly dedicated to helping out TF2Mix/Newer players be admins, Waldo and hooky seem promising definitely.