Provide a 'photographic exposure control' feature with familiar Aperture, Shutter, ISO, and White Balance (in Kelvin) settings.
When Advanced Lighting is calculated, allow the user to use familiar camera-based controls for exposure.
Ideally a customizable camera response curve would be provided, perhaps compatible with the response curves calculated in HDRshop; or else with a few basic but realistic presets (e.g. Tri-X film; Canon 1Ds camera etc).
This would provide much better and more intuitive control than the current (very arbitrary) Logarithmic Exposure Control, and could link in with cameras and rendering for Depth of Field and Motion Blur control.
Rendering --> Environment --> Exposure Control