As of right now, this is done: [the "vote down" privilege is awarded at 100 reputation here on Meta Stack Exchange](http://meta.stackexchange.com/help/privileges/vote-down). 

This should allow folks with the association bonus - or those who earn 100 reputation by participation here - to downvote questions as much as they wish (particularly important for feature discussions). It does limit downvotes on *answers*, since those reduce the voter's reputation by 1 point for each downvote - if you want to continue downvoting, you'll need to actually earn some reputation. 

It also means you can't just show up and troll the place non-stop and keep downvoting, since if *your* posts get downvoted you'll lose the ability to downvote others (unless you also participate constructively in other areas).