The 'dead air' perception seems like something which can easily be challenged. Space for the carriage of cycles, prams and large luggage becomes extra standing room twice per day, offering increased capacity for passengers on-peak and increased capacity for users with cycles, prams and large luggage the rest of the time. If you ask passengers for their views on this, they will be in support of it provided the question isn't designed to outrightly lead them to the wrong answer (Think Metrolink and cycle carriage in Manchester)
InterCity East Coast consultation opens today, for the usual 3 months.
http://www.dft.gov.uk/news/press-releases/dft-news-20120626c?utm_source=...
Should be of particular interest to York, Newcastle and Edinburgh.