I'm not sure I understood you exactly but what I get from it is that it would make sense if the total comments reward of a post should be some proportion to the reward of the post. Post with big rewards should gather more  reactions and comments and those should gather more weight/reward compare to comments on post with smaller reward.  

I'm not sure how feasible that would be but I feel this concept has some value. Posts and comments would most probably have to be 2 separated pool rewards.