It's been like two or three years since I last played it, but I used to kick back at playing BZFlag over the Internet (if you don't know the game, it's a CTF type of game where you control a battle tank - with lots of weapons and bonuses to capture and use from the map (or an enemy tank!), really whacky!).
A great thing about it was
you could join at any time in the game! No need to wait for "game start".
The masterserver details (on the menus where you chose which one to connect to) included, amongst other infos, how many players each team had on and you could still choose any team which sometimes wasn't fair, but usually people chose the team that had less players so most of the time it was levelled.
You could also leave at any given time.
You could actually also automatically get kicked out of the game for lagging! (first you'd get a warning, a little later if it continued, you'd get kicked; usually closing some open app you had on your PC would cut the lag off).
This was important as different people had different connection speeds (and hosts; your tank was entirely controlled by your PC which meant some had so called "modified machines" (cheats), really a nag
).
Naturally, in BZFlag, getting in and out of the game on a whim was ok as you controlled nothing more than a unit and it was setup so that units that were there for longer had little chance of having an edge over the others (you might have caught a better weapon or some bonus item but you could only use one at any given time so it wasn't that important).
In (Mega)Glest this is very different. If you get in when all the other factions already have their strongest units, you'll be dead in no time...
Still... I guess, in a way... it could be kind of a challenge for the newcomer and could keep the game going for longer for those already there. Potentially, the game could go on virtually "forever", where you would get in, slaughter as much as you could and then leave when you're tired of it.
So... in brief:
1. You probably want to setup some kind of anti-lag system on the masterserver so it can kick out players who make the whole game unplayable because they have crappy connections.
2. You could eventually setup the masterserver (as an option the server would choose and the potential players would be informed of) to allow players to join at any time. The "normal" option of the game only starting when all players were ready should still be available.
Other than what I said before, Titi's plan sounds great!