It has probably been asked before, but what does everyone want to see in the next expansion.  Ideally 1 new thing or 1 thing tweaked.

I want to add a new tab (f4) trading.  Take trading off the constant income and make each ship only cash out when it comes in to port in your territory!  Make it interesting, add 3-4 neutral trade ports scattered over the map (in asteroid fields) that give higher returns but obviously are more dangerous (other empires might park cap ships and pickoff the trade ships trying to port).  You can specify which ports to use or not in the trade tab, as well as talk to say neutral traders who might have intel on oposing fleets in their sector (they want to make money! they have no loyalty).  You can even add a "no kill trade ships" in diplomacy, while you may not trade in another empire, you will not kill their trade ships and they wont kill yours.  This can even open up extra tech options for trading, making an economic/research strategy more intensive, especially in a big map.  Could even make points of conflict over trading lanes and ports, but the neutral traders might be "bribed" into straping bombs on cap ships hulls if an empire is trying to suck out all the trading! 

I think diplomacy and economics and ways to attack on a second level would help diversify gameplay.  Now it is a matter of build the biggest fleet you can afford, crush the enemy, rebuild his planet, build fleet, crush enemy, repeat!!