This is not a bad idea at a glance, but I see one flaw. As I understand it, Steemit's definition of "post" includes not only full blog entries, but also comments. It seems to me that a limit of three comments (or one entry and two comments) seems a bit extreme.
I do most definitely agree there is a problem with reward pool abuse though, and in my admittedly amateurish opinion, a lot of bots are part of that problem. I mean, you can take a post with nothing but a cat picture and some gibberish, submit it to minnowbooster and a handful of other tools, and make 50 bucks off of it. Yeah, people could flag it but very few are paying enough attention o do so. Most just see "oh! High reward payout. ME WANT!"