Discussion:
    
Alternative was to pass AA-Quality same as SampleCount from the top (e.g. GraphUI Scene),
however, this convolutes the API even more.
Both parameter modify the resulting shader code in pass2 rendering (only).
    
The used 'renderMode' is still maintained within the Region,
since it contains more dynamic states individual to each Region instance (color-texture, ..).
This despite 'renderMode' also changes the RenderState's shader program.
In the end, it really doesn't matter and is a choice of frequency - the pipeline is
usually rendering from on OpenGL rendering thread sequentially.
AA-Quality and SampleCount simply usually don't change that often
and are set only once.