Doubt it, most people would still get on the first train they could find going to where they wanted to go to (the only time they wouldn't is if they physically couldn't get on the train) so you would probably find the first train is rammed and the second is fairly quiet.
Perhaps but passengers like clock face timetables it means they can quickly learn the timetable and know when there train will be always and anything that makes life easier for the passenger is worthwhile in my book. Also it seems to me that clock face timetables are efficient, why would we want two trains within minutes of each other and then nothing for an hour or more? Surely it's a better use of resources to have two trains every half hour (or roughly that anyway)? To me honest clock face seems to be something of a win win.
The modern timetable has departures from Bristol Temple Meads to Birmingham at xx:00 and xx:30 every hour from 07:00 until 20:30 (with one early morning at 06:15). Surely that's better than the old timetable?
Bear in mind that at the times when the services were running as intensively as just 7 or 8 minutes apart, one service would be heading to Manchester/Liverpool whilst the other would be heading to York/Newcastle/Scotland. And some of the services run non-stop up to Birmingham. Also the times of the day when there are gaps between services of roughly an hour to an hour and a half, would be at times of the day when less people are travelling. Looking at the old 1990 timetable of those departure from Bristol to the North, I can certainly see the sense and practicalities of such timetabling.
However I can certainly see the sense in the clock face timetables we have today. It's very easy for passengers to learn and remember. And if such "random" like timetables were introduced today, a lot of passengers would probably complain. I can see the headlines in The Daily Mail and The Metro now.... "Cross Country Trains introduce baffling new timetable....".
Even with the current clock face timetables, I do feel that at certain busy peak times they can manage to slot in additional limited stop services to ease over-crowding on the other services.
For instance one additional such service I've roughly timetabled to try and fit in with existing services.
Derby 1700
Birmingham New Street(arrive) 1743
Birmingham New Street(depart) 1755
Bristol Temple Meads (arrive) 1923 ( it could potentially arrive 10 minutes earlier than that, but I've included some recovery time)
Bristol Temple Meads (depart) 1930
Exeter St. Davids (arrive) 2024
Exeter St. Davids (depart) 2026
...And then the usual stops onto Plymouth or Penzance.
I do hope things improve on these Cross Country services in the near future. Either through putting extra carriages onto services(some of the services at least), and/or (less likely) introducing additional services to ease over-crowding. This is what I want the government to spend money on and sort out, deal with and significantly improve the existing problems on the UK rail network. Not go and spend £32billion on a high speed London-Birmingham line! Sort out problems on the rest of the network first, then look into building that high speed line.