After you've been here a while, and have hopefully started seeing how everything works (like a year) then you get 2 posts.
It would vastly cut down on the spam, as new members would save that post for something worth talking about.
If HT was really good he could limit the number of replies as well. Although I'd expect they would get a few more of those.
Even if it was for the first 3 months, 1 post a day. 2nd 3 months 2 posts, etc. Till at the end of the year if you hadn't been a total pain you'd get unlimited status.
Just a wish for a calmer quieter AH message boards. 
Or you could remove the post counter, resulting in people not posting for the sakes of just making another post to add to their counter. There are better ways to improve the quality of a forum without reducing the amount of communication going on in it. And to impose daily post/reply limits actually causes the forums to become less calm and just unreadable.
I like the idea of a calm, quiet and well organized forum too. However it goes against the purpose of a forum if you heavily restrict or limit the daily post flow and general environment of free-flowing information.
It's also very counterproductive for HTC's end. Say it's a patch day and there are multiple bugs in the game and the forum is useing a 1 topic, 5 replies limit. Good bug-reporting players know when one bug is completely isolated from another bug and when, for the sakes of not making it confusing, to report each individual bug in the game in it's own thread (this way HTC knows they have a bug with plane X, a bug with texture Y, and a bug with code line Z, and that those three separate bugs are not one single XYZ bug being reported from a single player). So now this bug-reporter has to choose which bug is the most important to report today, and which ones to que up and report when he can and as he can due to the forum restriction. So a post a day results in a player with a good description of 5 bugs in a new patch having to post about those 5 bugs over 5 days time, instead of posting them as he finds them.
Another way it's counter productive to HTC and everyone else in the game is that it prevents those players not officially associated with HTC from freely stepping in to provide help and support to new players asking for it. Friendly loves to teach people how to play in this game, and he could be replying to and helping 10 different players today with their problems/questions on the boards, but instead he now needs to choose which one to help today and which of the other 9 to put off until later or not help out at all. Everyone looses except for the one lucky nub who won the Friendly lottery today... and even that lucky nub probably has more questions he wants to ask, new topics to create to ask those in, and so this system is restrictive in them learning and getting into the game too.
And finally, the post limit you put in place to create more calm and quiet forums ultimately does the opposite you created it for... it will create countless incomprehensible, multiple-subject, multiple-topic, "walls-of-text" that would make the most hardened reader cringe while deciphering. Tell me, is it easier if a topic is broken down into it's own individual threads so that it can clearly be shared and replied to while not going off-topic, or is it easier to cram everything you wanted to talk about today into a multi-page novel that then needs to be picked apart subject by subject, topic by topic so that it's possible for people to reply to it as best they can without creating another wall of text?