Interesting thoughts there. I agree the comments are also possible. Steemit has a post on the @steemitblog in a comment that explains it could be done via comments. I've also talked to developers and they have said it can be done with custom json similar to how a follow is put on the blockchain except it would link two posts together and hide the new post, just activating that upvote button on an active post. Or just doing this if someone clicks upvote even to reduce spam.