Heh. Who was it that said "the whole reason we have a community is because armagetron is a promiscuous little slut"? Oh yeah, that was me.
I see your worry, Gnorty, and I share it. It's another thing that, taken moderately, could really enhance play, but taken to an extreme could really screw up play. You could consider we currently have the opposite extreme, where new players can come in and do whatever they want.
I don't know what the solution is. The idea of a practice grid is good. The idea of a waiting room linked to another server where people can play a more light-hearted game and optionally elect not to join the more competitive server when their turn comes up (and get put in the back of the line).
Any automated way of moving players up by merit is doomed to failure, I think. The caveats we all have with new players might be automatically detected, but can't be canonically detected. The only serious problem isn't that new players don't grind, don't break, and turn around and cut through the zone. It's that many of them *don't listen when you try to correct these problems*. So you resort to more extreme methods, like hunting them until they either leave or listen. There are some players playing today who didn't listen when they were new, that I (and probably others) hunted until they listened, who are now wonderful players. So with that being the problem, how do you grade players?
The only solution to this problem that I can see is through authentication. Give accounts on a special authenticated server on some sort of basis that filters out people who don't listen from people who do. That presumes we have some sort of authentication support (which sadly didn't make it into 0.2.8, grrrrr). This also leads to uptight elitist servers that have only small audiences complaining about wanting a larger audience, but too many of us will refuse to join over the elitism, and new players will be barred precisely because of the elitism. (sky and I had a bit of a spat over the "elite" part of his clan's name, but of course, he invited me in before they had named it and I declined back then on general clan-hating grounds)
Other solutions that are good revolve around letting the player in but putting him on spectator mode, where he can talk and ask questions. Maybe a "kick to spectator" instead of "kick from server". Then only send the console, you know, the chat. Then you can talk to him for a few minutes, work out the communication problem, and if you can get him to agree to listen to the team, you don't kick him from the server. Even then, I don't know. Using familiarity might be better. If the nickname is unfamiliar and the ip address hasn't been used in the last 2 weeks or whatever, then put him in spectator mode with a big hairy message that says "This is a team server, you will be expected to play as a team member. That means you'll have to listen, yadayadayada. Please take a few minutes to get to know the teams. This is not a threat, but unfortunately if you do not do this and you do not listen, they will likely kick you off the server, and we want you to play and have fun". You know, that stuff.
But dammit, it's not being new that we hate. It's not listening. You can suck as much as you want, but if you play the best you can, play competitively, and do the best you can to be part of the team, we really don't care how much you suck. I'll take an entire team of sucky good-natured players over a team of really kick-ass elitist snobs.