@AntoineBR It is cool idea but also has downsides. If you don't know which other factions will be picked, you can't correctly estimate the power of your faction in that particular game. You need to know in advance about your neighbours, their terraform distance, potential starting positions, gaia formers capacity, etc. Otheriwse you can't bid correctly. Image bidding for Itars which were picked first. It may appear as a great faction for the game, but if someone would picked Terrans as their last faction, Itars power dramatically drops as they gets another gaia planets competitor and very close neighbour. So last players has a big advantage as he has full game information and can correctly estimate which faction is the best for the game.
Anyway, no matter in which system factions will be picked, it never will be perfect. Bidding seems to be the most fair as each player has an opportunity to pick the best faction. And of course, it is annoying when someone picks bad faction for bidding. And maybe it is not fun to play such a faction as you know you won't get a good score, but still it is possible to win when you start the game with 20-30 points advantage.