This would never fly.
Unfortunately due to, ahem..... human nature, lol..... people always have differing opinions. I could start a thread that says God is awesome, and you bet you butt there would be 20 people who would like that post---Just as much as there would be another 20 who would call me an idiot.
Still doesnt mean it's not against the rules and that I didnt know it, regardless if there were 200 people who liked my post. If a forum member with either of our tenures started a thread like that, I'd say a slap on the wrist is most definitely warranted, just for being a dumbass and even trying that.
Just my two cents....
This also makes the rules less clear to people, and I bet you'd see a lot more "attempts" at getting crappy threads to make it through that 20 likes notion you are suggesting. Or am I misunderstanding something about your suggestion?