Yes.
Increasing downvotes is healthy and important for the ecosystem, so much so that I am still a strong proponent of a separate downvote power pool.
I agree with the other comments that downvotes should be more visually similar to upvotes -- it is an important UX decision that will be able to slowly change the culture to be more accepting of downvotes.
The two above changes -- separate downvote power, and equivalent UX design -- would go a long way to better sample both positive and negative feedback on a post and lead to more "fair" rewards.
One consideration would be the continuation of "flag wars" to "downvote wars". I'm not sure the best approach for avoiding this becoming more common (perhaps hiding the list of downvoters from Steemit's UX would help) but with more prevalent downvotes it is likely retaliation will increase. It is a consideration, but the benefits outweigh this concern in my opinion.
Finally, the new communities interface surrounding a new form of "flagging" should be robust. Moderation is very important for social networks, and having robust tools for community leaders to clean their space is a key element for having a good public image and leaving good impressions for newcomers.