I really like this idea. Do you have some starting values that could be posted in another thread that could be discussed further? Or possibly a thread could be started to discuss the weighting of factors.I've had in my head for a while the concept of a "situational" index for the available civs. Don't know how to best calculate it (we seem to be tiring of elimination threads and straight-voting wouldn't really work) but the idea is that civs range from 0 (i.e. completely non-dependent on map start for their abilities to be of use) to 1 (i.e. totally dependent on a proper map start.)
No civ would truly be at either 0 or 1, but I imagine France, Ethiopia and Babylon probably being closest to 0, and Indonesia, Byzantium and Iroquois being closest to 1.* France mostly needs a capital. Ethiopia is built to go tall. Babylon's uniques are all terrain-independent. Indonesia needs not just coast, but worthwhile islands and iron to boot. Iroquois needs enough forest to create trade routes, and Byzantium, yes, needs to be able to found a religion.
*I am including start biases in my rough-estimates here.
Difficulty in Civillization already goes way beyond the level being played, map type/size, game pace and other options can have a profound effect on a number of civs. As a result a number of the recent vote threads have been difficult because few experience all the settings with all the civs and they devolve into simple popularity contests.