I don't think you can limit steem (voting) power because it disincentivizes people from holding more steem. Over time, I think the distribution of Steem has been slowly getting better. Dirt cheap prices help. The whole idea behind this platform is that being a stakeholder gives you a say in its operation, whether it be via curation or witness voting. I don't think that we would want to do anything that changes that aspect of steem.
I don't have numbers to back it up but the last ones I saw posted by somebody showed that traffic was holding fairly steady. I think traffic will always be affected to some degree by the price of steem and for now the price of steem is still strongly affected by the rest of the crypto market which hasn't been great lately.
I think the recent hard fork has helped a great deal in terms of preventing bot abuse and I'm sure there are plenty more improvements that can be done. I just don't think you can change the fundamental idea that the greater your stake, the greater your influence.
I think we could use curation rewards to motivate people to hold steem and find a way to spread voting power.
I hope you're right about traffic but Alexa numbers for steemit have me worried.