Killing process by middle click.

For instance, it's useful when some window is freezing with "Always On Top" flag and it's hard to close it because of its covering other windows. Usually, it's related to OpenGL games which don't have real (exclusive) full-screen mode.
 

Это например полезно когда зависает какое-нибудь окно с флагом поверх всех окон и его трудно закрыть из-за перекрытия им остальных окон. Обычно это касается OpenGL игр у которых не существует настоящего (эклюзивного) полноэкранного режима.

This would be useful for those times when a problem app causes the mouse cursor to become very jumpy and stuck-in-the-mud, making task manager difficult to access.

'Kill Process' could be an additional registry value. That way it's there for those who need it and out of the way for others.

Please add kill task to Mouse Button Control > taskbaritem

I don't think killing a process should be allowed from the taskbar.

P.S. Task Manager has this feature, using the Ctrl key.