I have taken over 30 courses on edX in the past few years (many more on Coursera). Some of those courses used Piazza, most the edX forums, so I know both systems. I also was a Community TA so I know the (few) options a CTA gets on edX.

Overall, IMHO Piazza clearly has far more features.

That said, I still prefer edX forums simply because I hardly ever need any of the Piazza features - and the Piazza GUI IMHO is much worse than edX especially for the target group. After edX implemented the sort-option "by activity" and "show only unread" my major complaints were solved.

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By the way, since I hope you read this reply, the worst by far on edX is that the darn page just won't stand still!

Please stop the "convenience scrolling (by Javascript)". Also, the height of the page changes when I select a comment that does/doesn't fit in the viewport (long threads vs. no-responses-yet comments, for example, and that too triggers automatic scrolling.

Next, the size of the text box changes! I use Chrome to make it much larger to see my entire long and carefully crafted and formatted comment, then I switch to another tab to do more research for my reply, but when I click back into the textbox it shrinks back to its small default size. Could you please leave my manually-made-large textbox as it is?

No changes of scroll positions, no changes of sizes, no changes of anything, please. Not just in the forum, the course pages have the same annoying (anti-)"feature". I find it very inconvenient when the GUI changes under me, it's the GUI equivalent of walking on ice.

I would also enjoy a feature to "mark all as read", so that I can use "show only unread" at any point in time. Right now that feature forces me to have clicked on each and every comment before it is useful.

Life update would be "nice to have" too, especially for a TA (if it's too expensive for server-load, how about offering it just for the TA and STAFF user groups).

What is also missing is even the slightest hint (in the comment editor, or anywhere) that you support LaTeX style formulas! As well as some help for beginners how to use it.

I know Christmas was last month, but that's my wishlist :-)

What I don't miss are votes. That always gets misused, and it is of very limited benefit. I see the value of votes in forums on something like reddit, I don't see benefit in edX forums with a focus on Q&A. Especially not down-votes. Even the "pin to top" doesn't really work: At least 70% of users don't ever notice pinned posts. If there have to be votes, do it like Disqus: You can see who voted. Or instead of votes do what Github did in the issues comments.

By the way, why do you still have votes at all? They are only displayed if anyone specifically checks them in a given comment. They used to be shown in the comment overview on the left. Right now the "vote" feature can be removed and nobody would notice.

Some random ideas:

Feature: Allow Staff and TAs to post without their status. Just like on reddit. Not everything I had to say was "official", and one reason I turned down several invitations to be a CTA on edX was because I really hated to have a green banner around every single one of my posts. Too much pressure, and just because I'm TA doesn't make all my answers "precious".

Feature: Allow admins (TAs, Staff) to merge threads. For example, the introductions at the beginning where 500 people post their own "glad to be here" thread instead of using the pinned(!) "Post your introduction here" thread, or when there is an issue and 50 people each report it (even when the last 20 new threads are about that same subject, most people post immediately before looking at the forum).

Feature: Detect if you responded to this person in the past. It's nice and gives a feeling of familiarity to find out you talked to someone in the past.

Feature: Geolocation. Show where the other people (in the current thread) are located.

Feature: Combine Wiki and forum: From within the forum let people select comments and/or threads for the Wiki. Ask the for some additional information, like choosing a Wiki page/section. This can address the problem that good comments are quickly buried by all the new ones.

Bug report: It seems right now the "Section" or "Chapter" or whatever you call it is not displayed in comments.