Interesting thoughts, and yes, the spectral sensitivity curves are certainly something we don't spend enough time looking at. I try to raise this issue whenever we discuss filter factors and tonal contrast / separation.
P.S. I'll just add, for what it's worth, that after some initial forays into UV photography, I think panatomic x and type 55 are some of the most UV-sensitive films still in use. I suspect that their sensitivity remains high well down into the 300s. I'll be doing some tests at ~325 in the coming weeks.