I will buy the game as soon as I hits the store. I have spend like 200 hours on it already. It's just so good!
For MP mode I'd suggest: 6 vs 6 PvP. Limit it to the money so people start with like 200k (or whatever the host sets), you could even add restrictions like an easy option "No rockets" or "no shields" etc. and a very basic server list so you can join a game and drop out quickly. So if you want you could spend all day on one server and fight enemy player ships or you go in, die and look for another server. You could go even as far and add some kind of garage where you can design your ship and than keep it there and when you join you simply select one and are ready to go. There are a tonne of options and this makes the game so exciting. You could go even as far as add a capture the orbit system where you destroy all enemy ships around a planet orbit and than it's your team color, so the team who wins all planets wins the game etc. So many options.