There certainly needs to be something done to increase the consequences of self voting. Could you potentially use an economic solution?
Here are some thoughts:

1. a self vote still works, but it counts the same as voting 10x as far as deterioration goes.

2. A self vote converts steem to steempower - perhaps to selfvote you have to hold steem, and when you self vote the same amount of value your vote is worth is automatically converted to steem power. For some this would add a step to self voting - Actually thinking about this perhaps something like this would help drive more voting for other content?

3. Self voting doesn't earn you any money because it pulls from your SP then puts it into the "escrow" of a vote until that post pays out. Although the post still gets "paid" it doesnt actually earn you anything. Also doing this on some percentage basis?

Just some ideas - I think Public Humiliation is great way to start though.. and we wouldn't even need a fork!