In principle, if we want to increase ROI for investors, it should be done by changing those parameters, not by diverting author rewards to investor/spammers at the social layer.

I'd love to see something like that happen - where the "Savings" element took a higher proportion of the reward pool than the author rewards. I guess the downside then is that there's no incentive to power up.

If people could ever get past the terror of SBD prices being below $1 USD, doing conversions and arbitrage would be a way for investors to make money with STEEM while keeping it liquid, reducing their incentive to find "passive income" solutions that manipulate the reward pool.