I've never found slam doors a hassle ever since I was old enough to reach the handle
Can't say I agree with this at all, and I say that as an able-bodied 30 year old rugby player/gym nut. If you're carrying bags they're a pain, leaning out when also dealing with a tippy wheelie bag and a holdall was always awkward.
And I definitely wouldn't recommend leaning out of a moving train, given the multiple deaths!
I do kind of love the opening droplights- sat on said tippy wheelie bag in the vestibule of a packed GWR HST slipping through the west country on a beautiful summers day was quite a lovely experience, but there's a good reason why they're not around any more.
Being able to bash a button with your elbow is a lot easier when holding bags, or children (or get the kid to press the button!). Some people with reduced mobility simply can't lean out the train to open the door, whilst they might not have any issues with pressing a button.
The HST is great- but the game has moved on, and accessibility is a major part of that. Think about it this way- the VW Golf Mk.1 dates from the same sort of time period. It's rightly regarded as an iconic classic car, and I'd love a Mk.1 GTI. But to daily drive and commute in? No thanks. I'll take a new VW ID.3 electric thanks, and keep the GTI for fun on the weekends. Which is where the HST in unmodifed form should be- and is!
Right now, I'd have to put the Pendolino as the best high-speed train. They've revolutionised the WCML, they're comfortable and fast. They do definitely need refurbishing though, I'm just hoping Avanti don't ruin them!