I take the starting point I'm dealt 99% of the time; it is not very important unless you start on a small island isolated from other landmass by sea/ocean; or if you start a place where all you can see is permafrost/barren and peaks even after 2 turns of moving the settler.When you start a game, how important is your starting point? I personally regenerate if I don't have a river nearby. I sometimes restart if by gathering and scavenging I have no resources in my city vicinity. What's the bare minimum you'll "take"? I started a deity game last night, quit when I realized I had no resources (and only desert and no flood plains in initial borders).
Getting the worst starting location of the X best locations picked for the X amount of starting players is part of being on the highest difficulty among all the players; it's a handicap factor used in the code I mean.
Each plot has a starting plot suitability score (based on yield + bonuses and a river, coast and hill factor, within the fat cross of the plot) and the algorithm tries to pick a set where it maintains a good distance between all the starting plot as well as maximizing the total score of the set chosen. Then the plots, from high to low score, are given out to players from low to high difficulty.