It gets hard to draw the line between which properties we should pick up and which we shouldn't. Why not font name too? Why not color?
In the end we need to provide a way for vision impaired users to access java applications. To facilitate this we are investigating enabling 4419975, that is, if the user has selected high contrast mode we will choose a limited color set and bigger fonts. For this reason, I am closing this as a duplicate of 4419975.
Based on feedback from Jeff, it looks like the best thing to do would be to have metal pick up font sizes from the desktop properties.
DefaultMetalTheme, on Windows, will now pick up font sizes from the desktop.
As with the WindowsLookAndFeel you can disable this by way of the system
As reflected by bug 4668963 this has the ability to break backwards compatability, as such the default will be false. If developers want this functionality they can turn it on by the default 'swing.useSystemFontSettings', ie swing.useSystemFontSettings=true