[Paul1980au]

1 only facility (looking at star trek here) ie super shipyard that yields in SE4 would be 10000 resources construction per turn (can only be built once per empire if they have discovered the alien ruins) and can only be built on the planet which it was discovered.

Could also be troops on built on planet x have a 300% attack and defense bonus.

Some other good ideas coming forward here ie specific classes of wormholes that need to be discovered with advanced scanners - perhaps they are long range warp point links to the far side of a big galaxy.

Also up to 500-700 systems instead of the max now of 255. Very massive empires would be wonderful