But rather than that, how about doing a online style of play that has deathmatch and CTF style battles. I would find these to be great fun, and I'm sure it would bring a lot of people to the game, considering how popular MP games are.
Here are some ideas:
Deathmatch and team deathmatch: Pretty self explanitory. Everyone gets a ship (hopefully equal in stats and power) and blasts away at each other. Respawns are a must, unless it is a tournament style game.

CTF: Again, self explanitory. Place a cargo canister with a flag in it, fly a ship into it to capture it, and then return it to someplace like a carrier or station.
Warfare: Either the AI or several people are chosen to fly a destroyer or carrier, several M6's or M7's, and fighters for everyone else. So the goal would be to destroy the enemy capital ship. People can shoot at each other, unleash fighter drones, build preprogrammed laser towers in the heat of battle, drop SQUASH mines, and the like.
Race: So, the race sequence in Reunion wasn't that great, but with other people, it will be better. Start in a hoop like ring, set up course markers, and race.
These are all the ideas I have. It wouldn't be that hard for Egosoft to get server machines or whatever they use for multiplayer.
This would really improve Egosoft's space games. I know it's not going to happen in TC, but it could happen with the next game.