I would like to see a base defence mode where the Arks set up a base on x planet for x reason for x research and bam a flood of D cell monsters appear in the distance and shaaabam the defence begins.

Turrets like the ones in city can be upgraded, walls can and lights could be bought for night time raids and you fail when the scientists inside die.

Mounted turrets could be integrated lines of defence i.e. trenchs, laser fences etc...
Drop ships send you supplies every so often for repairs.

Thats my idea.