I’m curious how much of this would be ticked off by completing other goals, like a decent sized area for bikes and large luggage that still prioritises wheelchairs, like a decent sized loo that a wheelchair can fit in that also has a fold down changing table. Wider seats, more bins, a clear area for noisier passengers have all been asked for before. Help with boarding is the main one from the experience I’ve heard of directly, either in advance of a train leaving a terminus or a staff setting up the wheelchair ramp and letting the driver know they’ve sat down before leaving.
Care has to be taken with things like this and there is an element of be careful what you wish for.
Modern robobogs on trains do cater for wheelchairs and changing tables.
On the last point, I once worked a train as guard and arrived at a typical single manned booking clerk town station. It turned out there had been a visually impaired person's convention there and over 20 people plus over 10 guide dogs had turned up ad hoc for the train and requested assistance to board, change trains and so on.
Not a problem, the chap in the office closed his window, did his best to get them grouped by destination on the platform, and he, I and a controller who happened to be travelling on the train and used to be a guard himself duly got them all safely boarded and sat down.
The problem? It took so long to achieve there was a 10 minute delay to the train and they and everyone else on board missed a number of 10 minute connections (double the 5 minute minimum, of course).
Helping people is important but equally taking 5 minutes and delaying the train to get them settled if necessary will have consequences. Quick and efficient but still friendly on the part of the station staff with a decent hand off to the on train staff if provided (and there in lies the problem, if there happens not to be on train staff) to resolve any further issues is the aim of the game.
The new app under development allowing hand offs with notifications and same day bookings should if used correctly help greatly in this regard.