The issue I found, which I assume you are referencing Terry, is #2704. Even if we don't do all of what is proposed there, I think the default bindings for the history should be changed (I have not used any terminals that don't use ↑↓).

In my experience, very few people know of the history functionality (especially people new to Python - which is IDLE's main audience) and even many of those who teach Python don't know about it!

As for the other features suggested, I am not sure about a "previous input" option in the right-click menu, though it may be nice to have a separate history for commands and inputs (I didn't look that closely at 2704 so it is possible this is proposed there). I am not sure I understand the feature proposed in '3'.