As much as I'd like to see multiplayer I understand that it would take much time to implement it, so it's better to leave it for your next game, FTL Online

However, there is another way of making this single player game more bonding.
What I have in mind is online ranking system. You could have kind of old school HI-SCORE lists.
There could be 3 of them:
a) Most missions accomplished,
b) Highest streak,
c) Average missions accomplished per games played.
I think that it wouldn't be so hard to implement in game. Just add accounts, link them to your server and add a couple of counters. The gain, however, would be pretty big. Players would come to the website to check their status, they'd get ranks added to their names on forum, they'd play more to improve rank and so on.
So you would gain more popularity at small cost. And it would be great for us players.