I'm offering the idea that there should be some restriction against new users posting in 'Off-Topic' Sub-Forums.
I spend a lot of time in BnP/PoliScie discussions, and constantly see obvious multis abusing the forums for increase in post count and creating reputation.
It's a big problem in the betting forums with multis scamming/welching users. I think if you made it more difficult for people like do_NaUKI to build an entire guild of multis that belong to the betting forums, less people would be making multis.
example is #kx clan. Almost a quarter of it's members are the same guy.

Just want to see a restriction for new users that doesnt allow them to post in 'Off-Topic' Sections for a minimum postcount/time period/minimum transactions

This would honestly accomplish nothing. For multis any restriction would be minor inconvenience as they could easily spam other sub for +1 or do 1 fg trades back and forth with another multi

reported and voted no

You dont seem to understand his reasoning

What does his reasoning have to do with this.
Postcount restrictions will just be spammed elsewhere and nothing changes.

One problem is people who think more posts means more trust in trades but stupidity can't be cured.

This is not going to happen.
You should use this tool: http://forums.d2jsp.org/tools.php?a=1 and report multi accounts if You claim there are some, make sure to place solid proofs which confirm Your report.
Let me know if You have any further questions.