2) Improved PM system.
I am in favor, however if you improve the PM system you might as well improve the entire forum. WYSIWYG is what I think about, quotes-in-quote, and suggestions 3) and 4).
3) Improved profile.
I am in favor. I am thinking about "see all threads/posts" and not "add a photo of yourself".
4) Automatic notification for new posts in the thread you're replying to.
My suggestion, so I am in favor obviously.
5) (Automatically) Saving incomplete posts as drafts.
I am 100% in favor. These could be implemented as invisible posts, but which receive the current time when posted so they end up as the newest. They could also be set to self-delete after a few days.
6) Images/thumbnails in posts.
Personally I am against this. This is a programming forum. Most of the "tech support" we give is expressed in source code, not screenshots. The Lounge would be where this feature would be (ab)used the most, becoming a mini-4chan in the process.
Edit: new one:
7) Comment system for articles.
Currently the main feedback for articles is the stars rating. It would be nice to have a Discussion tab on articles (like on Wikipedia, for instance) where users could comment.
I like the list Catfish5 made. I agree with it. I also really like the Zero reply list idea. Comments on threads are A++ in my book (or C++ if we want to get punny).
I don't think there should be pictures, and I don't think there should be an option to edit other people's posts. Even if it is for getting a better understand and starts out with good intentions, it'll probably end in chaos. Just asking the person to expand on their thoughts a little more should do the trick.
Where are we on the topic of meta tags for posts? Honestly that and the Zero Posts option are the only functional improvements that I would be really excited to see, everything else is just "shiny".
It's kind of disappointing when I see a thread that says something like "How do I blah blah blah in Excel" and I know that I have code that is doing something very similar right now through COM+. It was tricky to figure out and I get excited about helping out. But then I click on the link and the user has half of it written in CLi, C# or Boost already. I think this would be a better option then simply adding more boards because it would allow for custom levels of granularity when looking at topics.
IMHO, I vote no on the pictures. It may be useful to see a screen shot of an error once in a while but we would have to weigh that minor addition of functionality against the truly horrific color schemes some people use on their desktops and the likely hood that people would start pasting screenshots of their code because obviously we're all wizards and can compile code just by looking at it.
Screenshots are also helpful because we have had several threads announcing a game someone made so they could showcase it some rather than just a download link to a zip with exe. I know some people are weary to download something without knowing what it is so that may help some.