I think this has been raised before, but I am unsure.
How about adding in random events, similar to MOO. Make it a low percentage (1%/month) and have a list of say 100 items, 25 good, 25 bad, 50 neutralish. Items ranging from increased/decreased tech point gain, income, shipyard output, etc.
Though as I'm typing this, possibly reduce the percentage to .1% per month, but make it cumulative. Once an event is triggered, the percentage drops back to the starting value.