In general the area near the doors is too restricted and crowded. Perhaps there should be some cars on each train that are designed as priority cars for alternative types of transportation like bikes and wheelchairs. The exterior of such cars should be clearly marked so that riders know which car will best suit their need.

If, as some other comments suggest, the overall design of the cars is to be examined, then opening up more access points, i.e. more doors, would be a great advantage to getting on and off the trains. Since half the passengers are standing during commute times, anyway, the elimination of a few more seats for better access would make little difference in rider comfort.