1)  Cruisers.  Of course the assault and carrier cruisers uses are obvious but what about support and support/repair?  Do support (increased friendly firepower) abilities stack?  Do you use repair on defense, or just try to fight near a defense platform? 

2)  Light frigates.  In the mid to end game what are they good for?  I know one drains antimatter, but what about the other races?  Sounds like they are more defensive because they can take out planet busters. 

3)  Refineries and trade ports:  Is there any diminishing returns on these?  Is it optimal to spread them out or have them at each planet.  Does the base population/income of the planet affect your decision to build a trade port or do they make income regardless of the planet?

4)  If you wanted to kill a bunch of long range frigates, would you send bombers or fighters?  What about scouts? 

5)  When you are on offense, what's the first target of your Heavy Assault Cruisers?  Do you try to mop up the light frigates, or do you go against the heavies?  What do you send after Heavy Assault Cruisers if you're short on bombers?