I think I like the idea of 3 separated pool rewards. At least 2 separated pool for posts and comments the way @arhag propose really seems to make a lot of sense. I'll be awaiting more tinkering, details and comments to make a better opinion of those proposals.
Also I'm not sure I understand the statement below. If comments don't have curation rewards then what will be the incentives to vote for those comments?
Comments should not have curation rewards because those who are reading have already found the discussion by other means.
What @smooth said is a no brainer in my opinion.
Voting up the most insightful, entertaining, etc. comments can be both non-trivial effort and add a lot of value.