With the current state of #development-discussion and its moderation/lack of rule enforcement, this is an absolutely atrocious idea.
New user creates an offtopic/against rules post (as a completely made up example for the sake of this post, “What music do you listen to while developing”) which is 40 points off the bat.
Due to there being next to no moderators who will do their job on the DD category this post will not be removed, leading to other users making pointless offtopic posts in similar themes to it. Free +40s all around for everyone who does that with next to no chance of punishment.
This will get an insane amount of replies (giving points to people encouraging this type of post) which lets the OP post replies talking about “ooh thats a great artist, I liked that one song by them” giving them a near infinite supply of +20s for themselves. 10 replies in, not including the original post or likes on the original or replies, that’s already 200 points. 1/5th of the point requirement for promotion.
The post will get crazy popular, an easy few hundred points from likes alone, as well as a constant stream of likes on those replies. Let’s say that the original post got 50 likes, and each reply got 5 likes. That’s another 100 points on top. 300 points/one third in to the requirement and the post has only just started.
From there it snowballs, not only giving the op a good 300+ points without breaking a sweat on a rule breaking post, but encourages others to make similarly spammy rule breaking posts.
Regular rank gets handed out to every single user out there, feature requests and bug reports go to hell after being overflowed with ignorant posts, the devforum has now gone from barely holding itself together by having #development-discussion be the barely moderated quarantine zone to a complete and utter shambles that nobody can use, much less take seriously.
Assuming that #development-discussion was properly moderated, the punishments you’ve suggested are extremely lax.
Assuming the post from my previous example does get removed, that’s only -80 off the 300 earned. Moderators won’t go out of their way to scroll an entire thread of messages to remove each and every offtopic one, so the rule breaker ends up with a net profit and just rinses+repeats.
It only takes making 2 replies to the post they made (totalling +40 and +40), and the rule breaker already broke even with the post deletion punishment.