This is a positive change, the old system when i signed up in 2007 was so frustrating, i remember i needed like 150 points and i gave up around 132 and stopped posting altogether, few years later i get a message i'm being promoted, and yes back then it certainly felt like you needed to write an essay to get points.
But i'm afraid only 5 posts will deter people from posting, it's like worrying about your low internet quota, specially when they feel they're being judged by everyone else.
I can imagine their line of thinking, do i post in the rafael thread? no feck it it's not worth it, do i post in the we're worried threads? they'll probably think i'm a muppet, do i post in the unpopular opinion thread? now isn't the time to be unpopular. Just make it 10 or 20 posts, it'll even help weed out the bad posters faster.