One long-term solution might be to spread footbridge entrances out along the whole length of the route so that even if people continue to bunch up on the platform, they are better spread out on the train itself
Those is a good point, one that designers could consider
Passenger spread tends to be better at Leeds, which has well used bridges at both ends of the through platforms than in York/ Doncaster/ Sheffield (where a central footbridge/ underpass means people mingle in one main area)
Other points:
1. Short forms are an issue. Even if it only happens 5% of the time, it means passengers will be reluctant to risk walking towards the platform ends
2. Better explanation re train lengths and First Class would help. Do I hear to the end of the platform only to find a single unit or (as has happened too often) that I'm at the First Class end and now have to head back towards the centre of the train? I think that these are part of the reason why London area commuters do better, fixed formation trains with predictable First Class locations must help encourage people to move along in anticipation
3. Weather protection! It's blustery towards the end of a platform. Can't blame people for huddling together like penguins in the middle of the platform
4. Whilst I take the point about the London underground, I've had situations where I've taken so long to walk from the far end of the Tube I've been on, battling through the crowds, that the next train has pulled into the station before I've made my way off the platform and into the passage way to street level. But I don't know how you solve this