Doing away with reservation chart pasted on coaches will create problems atleast in Kerala, as they sell deserved/Sleeper Class tickets for short distance travel. Usually passengers with such DR/SL tickets occupy seats after searching the reservation chart. Once they do away with chart on coach, it will cause difficulty for passengers boarding with DR/SL tickets from stations enroute. You'll be totally at the mercy of TTE to find seats & there won't be any chance to check availability independently.