I've studied lighting tech on and off since getting into planted aquariums in 2006 and remember that some researchers at Philips also lamented the issues with C

I've studied lighting tech on and off since getting into planted aquariums in 2006 and remember that some researchers at Philips also lamented the issues with CRI as a metric of light quality and presented their own system which I remember as being a color wheel with a lot of (possibly 100+) marked points. For each point, they'd present a vector as the difference from "actual" (as represented by the appearance in midday sun on a clear day) for a light source, so you could easily see how much a particular light skewed particular colors with fairly fine granularity. I neglected to save the source and haven't been able to find it in subsequent searchings though.