I am deeply concerned that this community thinks the problem is that the system isn't complex enough. Complicate payouts and who wins? The people with the most stake, because they have the highest incentive to figure out the new system and game it while everyone else gets fleeced.
No one seems to bring up the fact that Steem's learning curve is already too high for new users. Doesn't seem to stop anyone from wanting to change everything.
The curve you've proposed takes money from the poor and gives it to the rich. It incentivizes Sybil attack. Anyone with 1000 accounts can upvote each account a tiny bit and they'll receive even better rewards than linear.