This is something that exists on Ubuntu/GNOME (Dash-to-Dock extension) and existed in Unity, which is really nice. We can press Meta+N to open the Nth application in the task manager. I suggest that, when holding the Super/Meta key, that N number is shown over each of the applications in the icon-only task manager (until the 9th or 10th one), so the user can easily check what number he has to press (without counting), and to make that keyboard shortcut more visible. Unity did this, I think. Dash-to-Dock (on Ubuntu at least) does this when pressing Meta+Q, ou Meta+<any number>.
Would be nice, yeah
*** Bug 463298 has been marked as a duplicate of this bug. ***
*** Bug 471077 has been marked as a duplicate of this bug. ***
*** Bug 476704 has been marked as a duplicate of this bug. ***
*** Bug 446173 has been marked as a duplicate of this bug. ***