With regard to segments vs. miles, When I lived in LA and traveled on transcon's from LAX I never cared about segments. Now living in Springfield MO and using SGF as my home airport, segments matter as a predominantly domestic traveler. Going from 100 to 120 segments to retain 1K is a big deal for me. I can pack on the miles by going through ORD to go west instead of DEN or the opposite going east and probably qualify on miles in the future if necessary.
I usually hit 100K miles by the end of the year anyhow but its always close and I travel enough for work to not want to do any pure runs.
While some may say that 1K's on segments are a small group or unprofitable, the change impacts me as an individual and certainly others. Look at some fares from SGF to anywhere and you will see high $.
To the "miles" people who have posted comments of a dismissive nature to the "segment" people like myself, please show some sympathy / support.