The idea of adding a voting limit is good but won't stop the circle jerks because you just have to create more accounts and divide the votes between them to counter it.
And btw. there are also many more problems on Steem, multi account abusers, copy/paste upvote farmer and so on and the problem with them is that they are harder to spot than for example haejin and his one man upvote army/personal investor (who for example wouldn't do any impact to Steem when leaving just because well all he does is upvoting haejin)
The problem is that Steem (at the current state) needs a lot of active regulation to stop abuse because it has no real passive mechanism to counter them well atm it has many mechanisms which are benefiting abusers ...