Actually, wouldn't a few environment-specific buildings recreate some of the distinctiveness of the environments that did exist at the conception of the game (if I understand correctly, I wasn't there) and disappeared later ?
Like "Marine current generator" that would give a +1 per production bonus per planet size on all Ocean planets ? It could also give +0,2 per planet size on Terran too, as they have oceans (albeit smaller ones).
Then "Cloud turbines" that would give a +3 flat bonus on Toxic planets, and maybe a +1 to Ocean and Terran (they have clouds too) and even maybe to Gas Giants ?
"Lava extraction" that would give +0,2 production per population on industry-focused Infernoes ?
"Atacama Observatory" would give +3 flat research bonus on deserts ?
"Solar Panels Lattices" would give +1 pop per planet size for Robotic Metabolism on Radiated planets and +1 production per planet size for other metabolisms when focused on industry ? Half of that for Barren planets and Desert planets (without the bonus to robotic population on the later, as sand is detrimental to robots)...
"Asteroid mining base" would give +(0,5 per population/planet size) per Asteroid Belt in the system on Barren planets (the absence of atmosphere allowing for reception of asteroids without them being burned during their descent, and low gravity facilitating the process) and half that for Radiated planets ?
"Deep ice laboratory" would give +1 research per planet size on Tundra planets ? One fourth of that on Terran ones too maybe ?
"Holistic Ecology Network" would halve the cost of Gaïa Transformation on all Terran planets ? Maybe even allow for GT on planets Terraformed to Terran ?
I tried to make them powerful enough so that they'll make for a distinctive gameplay (and that players will tend to research the technology that unlocks them), but not unbalancing either - I may have failed at that but then more experienced players can help correct these propositions, if they agree that the core concept behind them is valid.