Restart button is available in all scripted modules. I usually restart by calling restart() method using python console (hit Ctrl-3, type "rest" then hit Tab and Enter), it just takes 1-2 seconds and only requires keyboard.

Finally, you can add your own shortcut for restart as described in the script repository, by adding this to the application startup script (https://www.slicer.org/wiki/Documentation/Nightly/ScriptRepository#Customize_keyboard_shortcuts):

<pre>
shortcuts = [
('Ctrl+b', lambda: slicer.app.layoutManager().setLayout(slicer.vtkMRMLLayoutNode.SlicerLayoutOneUpRedSliceView)),
('Ctrl+n', lambda: slicer.app.layoutManager().setLayout(slicer.vtkMRMLLayoutNode.SlicerLayoutOneUpYellowSliceView)),
('Ctrl+m', lambda: slicer.app.layoutManager().setLayout(slicer.vtkMRMLLayoutNode.SlicerLayoutOneUpGreenSliceView)),
('Ctrl+,', lambda: slicer.app.layoutManager().setLayout(slicer.vtkMRMLLayoutNode.SlicerLayoutFourUpView)),
('Ctrl+Shift+r', slicer.util.restart)
]

for (shortcutKey, callback) in shortcuts:
shortcut = qt.QShortcut(slicer.util.mainWindow())
shortcut.setKey(qt.QKeySequence(shortcutKey))
shortcut.connect( 'activated()', callback)
</pre>

The provided alternative solutions should be cover most use cases. Reopen the issue if you would like to have additional methods to restart the application.