General comment: I am less willing to casually change defaults or even remove features, and upset current habits of current users, than the blogger and responders.  I now have an organized list of all open Idle issues.  I am checking this list against that and am incorporating data from messages above.

1a. #2704 (limited from request) jump to prompt when hitting character key.
1b. (my idea) add run-undo that will delete output and reactivate previous input line for editing.
1.1 #3851,  #17060, #18444 HOME, fixed on non-mac,
1.2 copy on highlight. Rejected. I constantly use auto-copy to >>>.
2. Debug highlight.  If still true, probably only or worse on Windows.
3. 15308 Stop execution. (same as control-C)  Restart Shell (C-F6) does more that stopping a statement, but is only sure way to stop.
4. #13884 Tear of menu optional or gone
5. #7136 New Window -> New Editor Window
6. Pygame issue or perhaps fixed as similar complaints have been.
7. #10364 .py extension, #6804 and #6858 are related.
8a. Delete ZoomHeight.  Low priority, someone might use it.
8b. Tile Shell & Editor:  I would like to tile two notebooks (#9262).
9. Surrounding parens.  delete or make auto
10. #17942 Improve debugger gui.
11. #17721 Help button.  Also Improve Idle config dialog.  Maybe.
12. #17535 Line numbers in editor.
13. #694339 dedent with shift Tab.
14. #5150 Strip trailing whitespace: auto for .py (including trailing \ns.
15. Save dialog: Save, Don't Save instead of yes/ no.
16. #10747 Icon version
17. c-wheel, change font size (see turtledemo #21933).
U1. Specify argv when run.
U2. #19406 include pip (Win, Mac, at least)
U3. Detect if 2.x or 3.x code (could at least 
U4. Repeat of 1a
R4.1 Idle and input(); works now
R4.2 Idle and turtle; works now
R4.3a Highlight blocks #6804 in part
R4.3b 22354 Highlight tabs versus spaces.
R5.1 Mac focus issue.
R5.2