This came up in comments of @o1eh's post, too. Another idea that I like is the idea of an interest-only account from @michelangelo3, but unfortunately I think that would require blockchain code changes, so probably not likely to be implemented quickly.

A quick way to approximate interest-only accounts would be to start paying interest on SBDs in savings. I believe the witnesses could do that with a simple parameter change. Since we don't seem to care about SBDs having lost their peg, that might be worth considering... Although, the problem is (if I understand correctly), it would raise the inflation rate of Steem's virtual supply. Pro: more daily author/curation rewards; Con: dilution of people's existing stakes.

Back to the topic of your post, I'm not opposed to it as a "lesser of evils" sort of thing. Ideally, I'd like to see people stop polluting the blockchain, but I think the 2^nd best choice is what you suggest, partitioning the pollution away from the creative content.