I think that 'megathreads' aren't really effective at communicating player wishes on the EN forums, given how frequently people post. More often than not, they end up turning into a glorified discord chat room with a flurry of disposable comments. So even if you do post something clever that catches people's interest amidst the dross, it usually doesn't get the visibility that it needs for long enough. If a thread has 62 pages, you'll probably encounter the first page of comments when you enter, but how often do you actually bother to flip back to see what people were saying on page 54? This type of thread format, in contrast, is good. Not because forum-goers are going to necessarily sift through 70 pages of chat comments to find a hidden gem to upvote, but because you have a (relatively) structured OP post that players can pool their support behind.
If I had to offer a critique on it, it would be a lack of focus. The first two points listed are excellent and hit the mark on the bulk of the complaints across the past two expansions. But yet, there's only one line written on each. Of the remaining eight points, there's four fluff points about visual effects, glamour, and lore, one point reiterating that healing sucks, and one point about healer feedback being ignored. This is length for length's sake, and it almost would have been more effective as a two line post.
Of course, what's even more effective is to take those two to three key issues (i.e. a large amount of healer downtime and a corresponding lack of damage options to use in that downtime), and then expand on each one of those under section headers. I'd personally probably put a relative lack of playstyle diversity as a third point (why does every healer released have to be a caster?) But I don't think editing the OP from two years ago adds anything to it.
In Q+A, people similarly spread themselves too thin, either posing multiple questions at once or offering opinion pieces in place of questions. When you do this, you risk getting an answer that doesn't address your main point. You have to be selective. When you wade through the short essay posed as a question during the last live letter, the bulk on it is a mini-rant on fight difficulty and how tanks are clearing Asphodelos without healers. So the answer itself focuses on how Asphodelos was undertuned because it is the intro raid, subsequent raid tiers will be harder, and there's Ultimate if even that is too easy for you. But that wasn't even the central issue that you actually cared about in the first place.
In short, this is the sort of high quality thread that is needed, it just needs to be articulated in a more focused way.