AcesHigh, I agree with you, not knowing which server you join and even worse not knowing which combo you're gonna end up with would destroy the good online experience in LFS.
On the other hand, many of the popular servers have a track rotation in place, so you can't be sure which combo will come next when you join a server (unless you know the track-rotation, of course).
So, Instead of having one server running one car and having a track rotation, have two or three that do. But don't make them joinable just like that.
Instead have some kind of relay-server, to which you connect, which forwards you to one of the servers behind it. This way instead of having one server with 38 people on it and total mayhem happening, you would have two with roughly 19 people on them each, providing still a big grid, but maybe less mayhem. Considering the proposed Division-wise joining policy, you would even end up with two servers having drivers with closer driving abilities (e.g. measured in personal best time).
As I said before you would want to keep the ability to join the server with your buddies on, which could be an automated routine depending on an yet to be implemented buddy-list-feature.
Of course you would have to administer two servers instead of one, which will lead into the same situation why CTRA closed down. So that's one point you gotta find a solution for.
I also do see the problem, that it takes away the freedom of server-choice and it also will maybe even limit the amount of combos that are busy. On the other hand, having four independent servers running roughly the same combo (e.g. different car classes) with like 2 or 3 racers each is exactly the problem described in the original post. Getting those servers together on a relay server can direct all players to one server, thus having about 8 to 10 racers in it. And I think IHR proved that different car classes on one public server can work out pretty good.
Also you don't have to make it mandatory to use a relay server. You still can join any of the available servers out there (that are not connected to a relay server, that is).
I think the idea mdmx proposed is still far from being ready to be implemented, lot of factors have to be included in the design, but it is good to talk about it.
AndRand, I back you up on the extended "meeting-room". That thing definately could need some improvement. I almost never use it, since there is never someone in there (and I am on the FM-TS3-Server anyhow when I go racing).
One way to "improve" it, is by simply removing it. Instead have like a Contact List of buddies, where you can see where your buddies are racing and join them by simply clicking on their name.
I'm gonna go to bed now. Thanks for reading and I hope this constructive discussion continues.
Best Regards