In _some_ cases, I am not so sure. One of the problems (IMO) of the current railway is how a peak frequency is run all day, rather than the traditional (BR and early privatisation) pattern of a standard interval during the day and extras at peak times, which in XC's case would include summer weekends, Saturdays most of the day, Fridays after about 3pm, and Sunday afternoons/evenings as well as the traditional Mon-Fri peak. One could argue that filling the railway with huge numbers of trains all day every day is a problem in that it creates congestion and thus delay, and actually slows down journey times - as well as reducing capacity for where there is real peak need (could they fit more trains _out_ of say New Street or Piccadilly between 5 and 6pm if there were not so many contra-peak trains coming in?)
I'm not for a minute suggesting reducing frequency at any time of day or week which has any pretension to being peak, nor reducing the total amount of seats (rather, the same or more), but there might be places were a half-hourly 4 coach service could be replaced by an hourly 12 coach service with more seats and less congestion. Less overcrowding _and_ faster journey times.
Might be in the minority, but I know I for one would find XC travel more attractive on a less congested railway with longer trains which didn't spend significant time sitting at signals waiting for another train to clear a junction, and could quite easily fit my plans around a reliable, non-overcrowded, two hourly, twelve-coach service from Southampton to Birmingham, to take an example of a journey I do regularly. The service would of course increase to hourly at busy times, and there would be extra trains north of Reading.