You're right that OpenCV currently offers a few basic white balance algorithms (simple white balance, gray world, and learning-based ones). As for raw image reconstruction: OpenCV doesn't directly handle RAW processing pipelines—at least not in the sense that full RAW-to-RGB conversion (like Demosaicing with camera-specific color matrices or black level corrections) is part of its standard workflow. So if your idea hinges on manipulating RAW data, you'd either need to preprocess with external tools (like dcraw, libraw, or rawpy) or restrict your scope to sRGB-space improvements, which aligns better with the current direction of OpenCV's photo module.
As for your second question: OpenCV’s user base is quite broad. It includes:
Students and researchers, like in your class, often using it to quickly prototype CV ideas or learn the basics.
Industry practitioners, including those in robotics, AR/VR, automotive, mobile, and occasionally even camera manufacturers
Software Vision Applications: A lot of vision processing applications use OpenCV to tinker with personal photography tools, image enhancement filters, or even retro camera software.
So, in terms of prioritization:
Smarter white balance algorithms (e.g., illuminant estimation, color constancy using spatial or learning-based cues)
Color corrections
vignetting correction, chromatic aberration correction
Exposure, contrast, temperature correction and enhancement in color images