Making this a separate topic since I've seen this issue brought up recently here and here, and elsewhere.
But yes, on the subject of the comment form being on a blog's permalink pages (instead of @eviltrout's current method that requires someone to jump to the Discourse forum itself to make a comment), it was already considered by @sam when he implemented Discourse as his blog's backend. He mentioned it in detail with this blog post. To further this, he pointed out the fact one has to jump to a separate page to make an actual comment:
Before any of this, let me address the elephant in the room. Commenting on this blog just became way more complicated. I plan to address that, in a future update, this is a temporary state. I want to bring back the traditional commenting box.
He planned on bringing back the traditional comment box on each permalink (like WordPress, Drupal, Disqus, et al). But after a bit of time with this new set up, he had a change of heart.
That post I linked just now mentions something that's been happening a lot: bloggers turning off comments entirely. A simple google search brings up the entire mass conversation. Both sides are seen: yes you should, no you shouldn't.
But Sam brought up the fact that since he made that one single extra click (or few) to have someone log into a separate Discourse forum to make a comment, the stress of allowing comments went down to nearly zero.
I bring this up for a few reasons. One, this shows that it has at least already entered the mind of another main Discourse dev besides @eviltrout. This tells me specifically that they aren't idiots. They know exactly what they did (or didn't do) and the possible repercussions because of it.
Two, Sam's experience makes a valid point on a possible mitigation technique to be able to have one's cake and eat it too. One can keep comments enabled while having the experience be nearly pain-free in the long term.
Third, I agree with it. So much in fact that I was planning this set up elsewhere. I planned (and still plan) to post excerpts of my content elsewhere (like twitter, facebook, deviantart, tumblr, ect) but then have a link to a comment page hosted by me so I have full control over the 'official' feedback I get on a specific item. Sure, others can make comments elsewhere on their social media platforms; that's their right. But if they want to speak to me front and center, I planned on having full control. AND make that single barrier of participation to mitigate the crap open comments get.
Barriers of participation is not a new concept for online community management. A few clicks and an extra tab down the line won't stop someone if they really want to say something where you're going to see it. One comment on Sam's epiphany blog post shows one view of that type of reader that doesn't mind the extra few clicks:
The fact that the process of "jumping to another site to log in" involves me simply saying "yeah use my Google account" completely outweighs any friction in the process. It might take a few clicks and a few popups rather than just banging the keyboard and hitting send, but the fact that you piggyback off existing authentication more than makes up for all that.
In the long run, you have to ask yourself: "Do I want a high number of comments on my blog? Or do I want quality comments on my blog?" Everything about Discourse is the answer to that question: "We want quality".
I will say that I'm not throwing the dev's a good excuse to not implement it. My opinion is as useful as a submarine on a screen door most days. But I at least wanted to show and explain why doing everything "as is before" isn't always the best solution. I know @codinghorror said that in some form to me when I got heated on Discourse's lack of online presence. I still think lack of online presence is a big mistake. But hey, I can just code it in myself. I know nothing about Ruby, Rails or Javascript, yet. But if I want something, I'm going to take the time to learn it so I get what I want.
tl;dr There's good, legit reasons to not having the comment form on blog permalinks. In the end, you can always code it yourself, even if it means yak shaving some Ruby/Rails/Javascript research.