Sort:  

The solution is increasing curation incentive with a hard fork. It's as simple as that. The exact implementation of the change isn't as easy because of multi-accounting though.

Yep that was my first idea too. It will probably improve 2 things at once, because people also keep complaining that the top 10% gets 90% of the rewards.

Then you need to check out @rycharde 's latest post, it's advocating exactly this.

I'm thinking this is a very promising solution and would love to see more debate around it.