I've always wanted to reimagine the IET interior, and I'd be happy to model it in Blender since I have the software, but my skill is not strong enough...
But I'll have a go at describing it.
- Replace all the standard class seat's with FISA Lean's since they are the closest thing to an actually comfortable seat which meets the safety regulations.
- I wouldn't go for changing the first-class seat's, but they could do with a bit more padding so it has padding similar to the HST first-class seat's.
- Replace the seats with no windows with luggage spaces, since it makes no sense to have non-window seat's.
- Put KeTech PIS screens in every carriage. It seems out of place without them.
- Put the same amount of seats on a 5-car set's first class as a 9-car set.
- Increase the overall durability of the walls and ceilings on the interiors, as some can be loose, increasing noise.
Making an Ideal train is something for another time, but this is a starter.
This is going to be a very interesting thread...