Here we go again! We humans have a need to eliminate the ladder of success once we've climbed it. First lets consider some of your valid points:
1 -Deceptive Sales heading: Agreed some clear guidelines are in order, but total policing of creativity is uncalled for. You cannot effectively police subliminal selling, and most sales thread are geared towards that. I would suggest they implement subtle headline changes, but wholesale policing would not solve any problem. Backlinking, including press releases that generate links is frowned upon by UNCLE GOOGLE.
2 - Raise market place prices: Why even suggest that, when people are just trying to find stable income. Just looking at raw numbers, this forum generates millions of dollars in revenue. Those $30 and $97 yearly fees do add up quickly. You forget to mention the free services provided by the thread creator to moderators, that in itself is worth hundreds of thousands of dollars yearly. Based on my experience, it is the so called lower class people that create rich people. The bottom always feed the rich, if you look closely at the metrics. Substantially raising the prices will neuter the budding enthusiasm that has developed in this forum. Higher thread prices will mean higher backlinking prices, which will eventually result in less traffic and lower yearly sales figures for the owner. You toss price increases around without looking at the actual countries where members come from. The price increase like you suggested is a bad idea, and might just be the death nail for the robust sales thread. Substantial revenue is also generated from the STICKY post headlines. The forum ADS are based on user metrics, and based on what I see the spaces are always sold out.
3 - Implement security deposit. That again is a bad idea. Every engagement with any sales thread involves some type of risk. People already have paypal to dispute charges, and I am sure the administrators do not want to get involved in the murky world of disputed charges. Actually, most crooks here do it with all the legitimacy of purchased rank. I was duped by a reputable member for over $2000 and it was not initiated through a sales thread. You cannot regulate common sense, neither can you try to legislate it. Human beings must wake up and take responsibility for how and who they interact with. At present, this is probably the only forum that requires providers supply same services they're selling to a moderator. A good suggestion would be for the moderators to more forthcoming in their initial review. In my opinion, the system works perfectly for everyone, and any problems are minor and better handled by the payment processing companies. In fact, buyer reviews does a good job of weeding out the poor performers eventually.
4 - I have no issues with the freelancer section, as it's not a huge traffic generator anyway. Personally, I have only visited that section only once or twice, and it has no regular activity to be actively monetized.
5 - Drop-shipping/wholesaling - Not a huge traffic generator and I could care less what happens to it. It does not fit into the cliche of this forum anyway.
In conclusion:
I urge the administrators to move carefully, before implementing any huge increase in thread prices. This forum is a virtual online space and you do not want to make it too expensive for people to visit. While the OP has good intentions with his suggestions, his call for substantial price increases might just be the death nail to erase the enthusiasm that took many years to build-up. Many people visit here for so many reasons, and majority of them are from so called "third world" countries. When you look closely at the synergies involved, BLACKHATWORLD is a great place to buy sometimes high quality links, and it would be a shame to see that completely destroyed with a price increase.