If the image is scaled then the font will be a blurry mess anyway.
By the way this is exactly what happens when using bufferedToImage with a scaled UI: fonts are often blurry due to rounding errors forcing a resize of the image. This forced me to get rid of bufferedToImage components altogether, and Direct2D made this possible while maintaining good (even better) performance.
ref: https://forum.juce.com/t/alternatives-to-affinetransform-scale-for-ui-scaling/60543
Regarding integration challenges in the framework, I understand your point, but I allow me to try and convince you otherwise 
JUCE7 was indeed using greyscale but I would say the new hinting method in JUCE8 make the issues more visible.
I don’t know how cleartype integration could be addressed, but speaking for myself I would be happy with a global setting (be it a define or a runtime thing) that would do the right thing when enabled (ie using cleartype when it is set in the OS, and resort to greyscale for images).