Not top priority, but just a note that this could be useful to implement in the mobile interface as well. I often read medium length talkpages in via en.m.wikipedia.org even on my desktop, since I find that interface cleaner. The [reply] function would be a perfect feature for that if implementable.
Topic on Talk:Talk pages project/Replying/Flow
+1
I agree. Same here.
There is already a "Reply" form in every section and "Add discussion" button on top, for registered users in mobile view.
@Geraki To clarify, that's a completely unrelated feature implemented in MobileFrontend, and it works differently (it always adds your reply at the end of the section, with no indentation).
We definitely want to have our reply tool enabled on mobile at some point, and it is definitely possible to do that, but we haven't though about the interface yet (and about how to integrate it with the existing mobile interface for reading discussions, visible in Geraki's screenshot, which works differently than the normal view).
TBH I like that impementation more that the Reply tool. As I have expressed (and individually others have expressed the same need), most posts in a discussion/section not need to be indented and just put in the end of the section (not replying to a specific user/post).