I'm aware of the apply function and that was how I managed to workaround my problems. My main issue is efficiency. It would be nice to just create a pyramidal tiff from my huge big tiff and whenever I have to load and repeat some calculations the downsampling was already there.
Let's hope in future releases this option will be available (as well as a setfFullLevel and a setPixel functions - the setBlock kinda solve thins but is impractical in many situations)