Basically, any transit fare system needs to be convenient and beneficial for both regular and occasional riders. The system should be as broad as possible - working for all modes of public transit - and should be as transparent as possible. A comprehensive fare card system for regular riders shouldn't displace easy single ticket sales for occasional or poorer riders. The card system should incorporate daily/weekly/monthly passes of all types within the system, as well as including cash for additional tickets outside any pass. It should be easy to add money to a pass with cash or credit - ticket machines, online, ticket windows. In Philadelphia the system would ideally be compatible with PATCO (important) and NJ Transit (nice, but less important).
This isn't rocket science.
