I admit that the Class 142 door buttons are poorly positioned but I don't think the other examples you give are particularly troublesome. Although it's not always welcome it's a fact of life that things are constantly changing and that includes transport. If the differing equipment positions on these trains are going to cause hardship to their users then how are these same users going to cope with everyday life where very little is standardised.
As for the old slam-door carriages.....Opening the door was easy. It was how to get the window open in the first place that was confusing.
