The concept is great with hospitality but still some planets should remain impractical to establish early game on as in class 1-7 or 31-39 in my opinion because it just keeps a sense of realism although this is GalCiv. Furthermore stating that fairly high and extremely low class planets shouldnt be colonizable should be due to the extreme enviroment as in a very hot planet, with lava rivers across some areas of the landscape or the oxygen or something of a beautiful tropical planet, whatnot cannot co-op currently with the species. I know this concept seems unfavorable due to a player finding a purple star system than suddenly another Civilization comes and can colonize it but I am suggesting this because seeing this humaniod species go about on some heavenly worlds or hellish spasas hits my game-realism side alittle. I just had inmind technologies for altering your species DNA for life support onto some enviroments or materials, energies and structures to sustain life on a particular planet as in GasGiant o