Your ideas are intriguing to me and I wish to subscribe to your newsletter.
Seriously though, I agree with your points. It's near impossible to massage user-contributed content in places like a forum unless one is willing to heavily re-write ever post a user makes. Should one actually try doing that, I think they will find out quickly that people don't appreciate such things.
I especially agree with the notes on "friendly urls". Using something such as that is expensive (in computation time), so it should be avoided. As for the readability and "friendlyness" of them, let's make a few real-world examples.
First, the standard SMF URL:
Here, you only really have to remember the topic ID number. It's not as easy to memorize as some things, but it's not super-humanly difficult.
Now, a sample "friendly" URL:
I think that perhaps this might be easier to memorize than some of the more common topic titles, but you suffer a bit here from the length and time. Four hours later, if you try to pull the page up on a different computer you not only have to still know the topic ID, but now you have to try and remember the words too! Was it Britian or England? Eat or Consume? Of course, if the rewrite is working correctly (pulling only the ID at the end), the following should take you to the same topic:
This means, of course, that the software will need to find some way of signaling to a search engine that such a URL as the above is not the correct URL either through the fairly-new canonical link tag in the page header, or via redirect to the "correct" URL. Of course, this means more computation time is spent making sure that the URLs are preserved instead of, you know, serving the page.
As for blogs, the canonical URL usually has a date in front of it to prevent URL collisions, which make "friendly" URLs on blog posts an oxymoron as you then have to also remember the year and month of the post and possibly the day as well.
On the topic of using heading tags the right way (in other words, not sprinkinlg h1-h6 in random areas you think are important but as actual outline elements), I support taking the time to do so if it is possible. Anything that can help the search engine distinguish between content and wrapper should be encouraged. This is especially important if you have the advantage of getting quality content-filled posts and topics.