Control/Flexibility is always best. :)
It is sometimes not easy to explain, bug gamma does not offer any control or flexibility. It is simply a difference between displaying output correctly or not. If pictures with gamma 2.2 look wrong to you, then you should use post processing to adjust them to your liking, or use less than 1 HL compression value as i said.
Sounds like you're understanding gamma as an post-render thing only, while it actually has to be considered pre-render, when textures are handled with a correct de-gamma correction so they look correctly when rendered. That's why you tell max what gamma you're using so input values are passed correctly to the render engine. Am I getting this wrong?
Keymaster, I for one actually would want gamma to be a 'variable' throughout the whole renderer, otherwise you can prepare for seeing 'bug' reports because people actually need flexibility in all kinds of different workflows. While I realize the above posted paradigm is good (!), flexibility doesn't automatically exclude this from being achievable :)