I agree RC can use work over time.
Right now there is not really any relationship between RC and block size because RC is a "long term" resource manager (growth in blockchain resources over a period of days to years), as well as limiting spam by very small accounts. We don't really have anything to manage resources in the short term on the time scale of blocks (seconds to minutes), but I have some ideas about how this could work.
I agree in terms of long-term growth. But for really efficient usage, a "short term" market maker can "plan" resources on peak times the most efficient way. Sure that's an ultra-complex thing and maybe it's not needed, but I think the idea is not that bad.
Maybe with a buffer system - delayed transactions, but cheaper. The idea is not for today's usage, it could be useful with 100x more transactions :)
It's only to allow a smooth usage with "fair and efficient pricing".
Btw, I would be really interested in your ideas :)
It's probably possible to optimize RC usage even now, since the prices are continously changing. I don't know if anyone is doing it but if so I'd guess it is mostly the account credit claimers.