As long as it's possible to agree on a number of benchmarks for every style, this could be the way forward. I'm not sure this is as easy as it seems though. Just to illustrate this, a couple of the problems you mentioned (Radja O.G (with the broken hold) and Ode to the modern man) have already been suggested to be 8B, rather than 8B+.
And as you say, the harder it gets, the fewer repeats.
I think it's important to treat grade suggestions as exactly that. Suggestions. Especially as, which everyone who's made FA:s know, grading a new climb is extremely difficult. Until there have been enough repeats, the grade hasn't settled. So, if someone repeats a problem with the suggested grade 8C, and thinks it's more like 8B+ or 8C+, this is also just a suggestion.
Eventually, after enough repeats, it will be possible to give the problem a more permanent grade. An average grade really, because it still doesn't mean it's the same difficulty for all.
To me, "8B" means "somewhere in the 8A+ to 8B+ spectrum for most people".
What do you think?