I would be careful to review the entire backlink profile. Google is good at ignoring many links. It might be that a small handful of links are what is really responsible for your link power.
I would improve quality by performing quality link development. The more good links you gain, the smaller percentage your bad links become.
-Go after relevant link partners. If you have good traffic it will be easier to exchange links with other leading websites. -Submit press releases not for a backlink from a low value pr website but because you have something so interesting you want people to know and write stories about it. -Offer free online tools and downloads that users want. If you offer something of great value, people will link to you without being asked.
And don't forget that backlinks are just one part of a very complicated ranking algorithm. Freshness and user engagement can significantly boost rankings.