What I would like:
- When I hold down Ctrl (or Cmd on macOS) for a second or more, show a little number just above or below the tabs which I could potentially switch to. Then I can easily press Ctrl-5 to jump to tab number 5.
Motivation: This would help me to switch to the tab I want, without missing and having to try again!
Why a second? Because people use Ctrl for lots of other things, so we don't want this feature to trigger all the time.
Why a long delay doesn't hurt? Because using this feature will help the user to remember the numbers (especially for pinned tabs, which rarely move) so over time the feature will help to make itself redundant. It's only needed when the user is unsure (which is likely the case when they hold down the Ctrl key for a long time).
This feature should probably be optional, because some people will probably want to turn it off.