[@Willy Vereb]
When I get the OOC setup, do you mind being the co-GM for the reasons you and [@Darkmatter] brought up? And if not, then [@Darkmatter], would you be the co-GM? 

The OOC will include everything you've said, btw. But I'm still going with more... restricted fleets. Look at the world today- there aren't more than two dozen aircraft carriers total, in the entire world. 

I'll also be including the fact that habitable worlds are rare. Population centers- and therefore, large-scale industry and economics- will be spread out more than usual, and colonies would more common. Planets outside a liquid water zone that don't have an atmosphere, but may be ideal in size and resources, would have to have dozens of terraformers constantly going to keep the planet stable, with a stable global climate. Again, it puts a bit more emphasis on strategy- controlling terraformers means essentially controlling the planet's surface.