My "complaint" (I used to fly them a lot) was not the lack of assigned seat, but, on connecting flights, arriving to City B and receiving boarding card #103, for what could then be a 3+ hour flight with no remaining carryon space and a middle seat. My suggestion at that time was to reserve some boarding cards in the 2d group for those who had already checked in @ point A. I think the rest of their system works quite well for efficient reliable transportation, and that pre-reserved parts of the aircraft would be a poor idea.