TEP:
This has been among my golf holy grails for several years now: having bogey ratings published, which would lead to better understanding of what slope really means, which would be beneficial in many ways, just as you say. We are compadres on this, mi amigo!
Unfortunately at least here in Northern California, there seems to be little interest in making this happen. I did query the NCGA course rating / handicapping officials this year re this, and they said there was no interest from any club in the subject, and further, asking clubs to re-do their scorecards was not something they wanted to do. Disheartening, huh?
To me the real value might come just as you say - that LOW SLOPE would be what's valued, not HIGH slope, as it so misguidedly is now. Then courses would be built that challenge the low 'cappers and allow the high 'cappers to have fun... instead of the all-too-penal monsters that seem to be built these days, with clubs falling over each other to set new slope records... The idea should be to compete to have slopes UNDER 120 - not OVER 140, as it seems to be today.
Oh well, I sigh wistfully.
In any event, I've posted nearly exactly this same lament as yours twice in my time participating in this discussion group. It met with no interest each time. Here's hoping the will of THE DOYEN will help in the effort!
TH
ps - interestingly, we have a course here in the Bay Area with a high course rating and low slope - many regulars here have played it - Monarch Bay - it gets generally poor reviews, for various reasons.