Im kinda not too sure about the randomisation of planets on some fixed scenario maps.
A map like Kharak Cross , has the 3 planets near the sun randomised between Artic/Volcano/Terran/Desert . I think this is okay because whatever the planets are , its still fair for all 4 players as they are equally contested.
However there are some fixed scenario maps where the randomised planet is just going to be colonised by one team , so its unfair if one team gets a terran on one and the other team gets a desert on their respective planet.
I think that on some fixed maps , the closest planets should be randomised but equal for both or four players. So forexample , in one game the planet to the right is a volcano for me , and its the same for the other player , then in another game it will be terran , but it will also be terran for the other player. Any planet that is further away and contested can be randomised to whatever.