I want a platform-independent text-shaping and rendering engine for fonts

Apple has created a mess with its overly solid interpretation of fonts, but there are many mismatches how type gets rendered and which anti-aliasing is possible. Sub-pixel optimizations are normally blamed, as the best implementation of them in ClearType is proprietary. However, Chrome on Windows is overly sharp, making thin fonts unusable.

There are a bunch of weird hacks and workarounds (with greyscaling, text-shadows, etc.) to let text appear more blurry, stronger in contrast, or similar. With variable fonts the risk is high that we are going to crack yet another nut with a sledgehammer.
On the other hand, there does not seem to be much engineering power thrown on the entire freetype stack. Browser vendors should be fixing that.