I love the idea of this game... But you're going to die out if players start thinking this game is dead and telling potential buyers not to invest because there are no servers...
I think after the next alpha release... you should get some developers to focus on improving the multiplayer experience in some non-gameplay related ways
by that i mean something like a master server list (i think that's the term i'm looking for)... so when we start the game, we get a list of all running servers, and a tab with server's we've favourited or previously visited... This will promote people running servers, It will provide an easier way for players to find online servers that have active players (if you let us see the number of players online... which would really be a must). Being easier to find, makes it easier to justify spending a little money on a dedicated server.
I would also suggest running a few servers yourselves. Contact some reasonably priced game server hosts and enquire about their service hosting your game (ties in with getting players to run their own servers 24/7... If it's as easy as click, pay, play.... you don't need to mess around with FTP to upload the relevant files etc). At the very least, if you guys can get your own servers running 24/7, your players can start being MUCH more active... which will ultimatley speed up your development process.... More active players means more chance of finding bugs (you probably already knew that)
Moving away from the multiplayer aspect a little.... You NEED to keep your players interested... they need to believe this game is still being developed.... realistically, they arent going to check this website daily .... I've only had the game a day... so i dunno if you guys have an updater distributed with the game... But i'd recommend some way to make players know there's an update when they run the game, and then, you can try to push out weekly, or monthly updates (even if they are hotfixes or tiny patches that fixes one bug a week)... this will keep your players interested, they will be looking forward to the next update to see what you have fixed or added.
I hope you'll seriously consider these tips... You NEED to make this game's player base more active.... at this moment in time, i wouldn't recommend buying the game to my friends because it is clearly designed for multiplayer, but there are too few players actually playing.
on a non-critical note... i LOVE the concept and hope i get the chance to play this game as part of a community soon :D