Currently there is no way to increase society levels, other than it going up once per turn (as long as you've played in the last 36 hours). I do plan to have other ways of increasing society level though -- mostly through things like foreign trade.
The cruiser is not the most cost effective unit in the game, according to my carefully thought out testing system, that would (arguably) be the Battleship. They also have a higher tendency towards catastrophic failure (meaning the outcome of cruiser battles swings widely in comparison to other types), due to their lower relative defensive strength. If you look at Planetary assault alone, they might be the best. They are a lot like cruisers in WWI -- fast, sleek, sexy, but unpredictable.
Still working on the trade system, which is also were the slowness comes in running the turn -- I'm removing a whole bunch of redundant queries, it should be quite a bit faster now. Should get it up in a night or two.
