"An application can be rated as Platinum if it installs and runs flawlessly ‘out of the box’. No changes required in winecfg."
http://appdb.winehq.org/help/?sTopic=maintainer_ratings

This is a dream goal, might be impossible, this would mean that most bugs/issues do not require a workaround. To acquire this rating, bugs fixed with workarounds need to have those workarounds implemented in the latest Wine version. Since MonoDevelop is an optional and independent IDE, having it work fully is not required for this rating.