Honestly is a downvote even needed? And if YES then there is a bigger issue.
If someone is going to come on here and just post garbage but has a ton of steem power to their name who are we to say they can or can't post it ?
The only time I have ever seen downvotes really used was when whales are attacking other people which seems totally unfair.
Why not just leave it as only upvotes. You have the choice to upvote good content but if you don't feel it is worthy well then simply you don't upvote it.
This to me seems like the easiest solution to everything.
Perhaps something else needs to be looked into if we are worried about crap content being upvoted crazy high. Or then again maybe we shouldn't care if they are holding a 300k steem power up ?