You raise some good points @thedegensloth. I agree with @nonameslefttouse regarding the Apps. It is quite possible people will move to the @smartmarket style of vote selling. I consider this less problematic as at least people keep their Steem Power rather delegate it away, therefore they can still curate whenever they want with ease.
Higher curation rewards combined with more downvoting, adds risk to selling votes to lower quality content. I think it is possible that good curation may actually be as profitable as selling votes. The same can be said about self-voting low quality content.
I think the proposed changes are worth a shot. I find it hard to imagine that we will end up with less manual curation than we have now.