Would it be possible to add a single late game vehicle that is capable of building everything that the lower model builders are capable of producing? This would allow people to cut down on builders and would cut down on processing power required for larger cities.
For LIS (and human, Insect is similar, i don't remember the alien), we need two building, Small Vehicle Factory and Robot factory.
Having multiple Vehicle is not a big problem, in any case for end game we really use only one vehicle in very large number (the turbo drone for build storage, ship yard, star port, converter, big house, stargate..). Having multiple Vehicle in end game help to fast build, because each type have a purpose, Builder bot, clay bot for road, Megabot for trash and hospital, Et builder for alien structure, ecc