According to an article in Phoronix http://www.phoronix.com/scan.php?page=news_item&px=FreeType-2.7-Released the 2.7.0 release includes much better sub-pixel hinting and I quote:
FreeType 2.7 also has improvements to its smooth rasterizer to make it about 20% faster, fixed for handling of raw CID fonts, fuzzer fixes, and various bug fixes and other improvements.
Maybe worth taking a look when time and scope allows, for further integration with our "optimized" desktop strategy.