Passenger Focus is the official "passenger's voice", though funded by the DfT so it tends to concentrate on issues that relate to whether train companies meet the letter of the rules imposed on them, rather than the more general question of what's good and practical to provide for passengers.

Their latest newsletters are available for download from:
http://www.passengerfocus.org.uk/what-we-are-doing/stakeholder-update/

and amongst the subjects that passengers have been telling them the need are more frequent services, and ticket offices manned by real people for longer hours.  Totally agreed - we certainly need a more frequent TransWilts service, and let's see if we can get up to a level of 12 ticket sales per hour at each of the stations which is the threshold set under certain franchises for requiring a ticket clerk to be on duty.