Simple answer - I wouldn't. If by quality content you mean what is organically popular, then you have Hot and Active. If you mean quality by some arbitrary judgement, then you have Feed and mechanism of resteem. There would still be problems arising from the fact that money dictates voting power. I'd see reputation revamped and made into deciding factor when it comes to rewarding authors. Since unlike money, reputation is not transferable, there would be no need to limit time when your vote gives reward. After all we put "the best quality content" in libraries and museums where people can pay to see it not for just 7 days after creation, but throughout centuries. Same should be true in Steem. In such setting authors wouldn't need to draw attention immediately, they could focus on lasting quality instead and it would naturally fend for itself.
Elimination of curation rewards is a small step in that direction.