I think the rule about randomly picking civs isn't fair. It would be better to pick the way the rules say in the original civilization game (the one from 1982 before adv civ). In the original game players would draw numbers from a stack of cards. The lowest number would pick his civ, then number 2, etc. In this way no player would get a civ that was isolated in a advantageous position, or choked by other civs like Thrace often is. The choosing would create a god game balance.

expansion rulebook text:
"14.4 Players randomly draw one of the available civilizations to play, takes the set of playing pieces for that nation and places one token in any one of his nation's start areas. Players may exchange starting civilizations if both players agree."

I like the original way better too, but the problem is the time it would take to set it up with 18 players to choose instead of just 7.
And in the new rules you are to remove part of the map if you aren't 18 people, so it will always be equaly "choked" everywhere, so that won't be any problem.

I'll probably try and devise an optional bidding mechancism for choosing what you play...