Diff needs a shortcut key
Being a revision control system, a very frequent operation is doing diffs between revisions. As such, a shortcut key would be very convenient for this function. When I have two revisions highlighted or two changesets highlighted, how about a Ctrl+F or Ctrl+D to get there.
And while you're at it, anything else that does not have a shortcut key needs one. Don't want to be reaching for the mouse all the time.
Walter Nicholls commented
This is still sitting as active, but doesn't Ctrl-D work now. (at least in version 18.104.22.1688)