Some people have requested support for more than 8 bits per channel support in QImage. This requires support for reading/writing, painting and transformation of the new formats.
Support for new colorspace models have also been suggested - like HDR and HLS, which are useless without the support of a QImage format that has more than 8 bits per channel. Most likely these these formats needs to be linked to some external library for reading/writing and/or color manipulation.