Plusfabi, Roman and Fabian has started work on a proposed redesign of Taskmanagers tooltips and these are the mockups provided by Plusfabi with the top row being my suggested edits to his mockup.
Please note that these are preliminary and by no means final!
additional information that didn't help someone. other tooltips (system tray) aren't the same size (big) so the tooltip for the task manager could be also smaler