Whoops, I seem to have blanked on everything discussed previously, my bad.
Also, after playing around with it, I’m coming around to agreeing with the “why do you need to quote reply in new topic anyway?” side of the argument: Once you have a compose window open, it is really not difficult to select and quote after that. It would also have the same flow as copying multiple quotes into a new topic.
One more thing, prior they were referred to as a “Linked Topic”, now it is referred to as “New Topic”, does the clarification matter? 
Sorry, that is my own use of incorrect terminology, it actually should only embed “Continuing discussion from link to topic”, not quoting it.
Two separate issues:
The “continuing discussion…” vs blank I agree – should populate the new post with “continuing discussion…” in the composer.
The second issue that I was responding to above is the ability (or lack there of post-timeline) to select a hunk of text and hit “reply as new topic” and have the composer auto-populate with the quote. This was possible pre-timeline, but is no longer with the removal of the “reply as new topic” gutter link.
Oh, I see. Sorry. Yeah, and the placement of the “+ New Topic” prevents that from working, as your selection is removed when you click the post timestamp or the share button.
I think it’s fine to quote after the fact. Again, we’re talking about an extremely rare action in the system here. I’m not sure we need to gold plate this one…
Whilst not 100% on this idea, it might be reasonable include a menu option.
Perhaps the options here aren’t quite correct - but hopefully this shows the idea.
You could also perhaps slip “Official Warning” and “Whisper” in there as options too.
This would also open up a place to indicate a “call” type as required by Start a new conversation with a customer not yet in Discourse feature request.
The idea is to change the type of reply whilst editing.
In the same way as now clicking the reply button on a topic / post would continue to change the type / or update the “linked topic”.
Oh, that’s a really nifty idea. 
A bit of a power user hidden thing, but we could make that more obviously a button / selector as well.
I tried sticking with the standard grey button on the mock up…
… I thought blue would be too loud.
Grey and grey - so I added a small border.
So my only concerns with that approach is the first and last obviously require knowing what post they are associated with. If the user uses the topic reply button or the one on the timeline, which post gets associated? The very last post? The first? The top post visible in the view port?
I would imagine that by default when the first option “Reply to post in topic” is selected with no existing post reply button used…
The “Reply” button in the composer would be disabled / prompt to “select a post to reply to” with further instruction…
… alternatively giving the option to “reply to the end of the topic” where the type of reply is changed.
That sounds… complicated.
One request that has come up, is sometimes people want to “switch” their reply to a different post target or the topic itself. This is already possible, actually, by simply pressing the desired reply button on the page before you submit your reply but this would give people another semi-obvious way to clarify their reply before they publish it.
I’m suggesting that this doesn’t change and this continue to be the way to select the reply post.
Regardless “Reply to post in topic” could be removed as an option from the menu and continue to use the current methodology for this part.
This would also make more room for the other suggestions.
I really like this design. Don’t forget the “replying to closed threads” use case…
FYI – As an end user, I was trying to reply as a new topic this morning, couldn’t locate the feature, and ended up googling my way to this thread where I discovered the feature to reply in a linked topic was moved under the age of the post.
Replying in a new topic is an incredibly useful feature to keep off-topic posts from derailing the current topic. As an end user, wanting to reply but knowing my reply is off-topic, I was expecting something like this:
I guess it depends on your perspective: are you (1) creating a new post for which you need a link to the current one or (2) replying to the post without disturbing the current topic. My experience with Discourse has more commonly been the latter.
It is in two places, use the link icon as well.
Very, very few people used this function even though it was shown (excessively, as it turns out) in the right gutter next to every single reply…
I love this drop-down proposal!
In our case, since the "reply as linked topic’ link was dropped, it has strongly been the latter, but not just. Frustratingly for me (the moderator), new posts have decreased tremendously too. People just don’t feel like starting new threads now.
Continuing the discussion from "Reply as new topic" button next to reply button:
The lack of use of a feature doesn’t necessarily indicate a lack of importance. Think post import on Medium or InMail in the early days of LinkedIn. That small amount of usage drove far-reaching behaviours overall. From this data-driven angle, is there data that shows how droping this link has affected broader behaviours? Like:
I’ve seen these change significantly for the worse on my forum. Particularly the last point, where people can’t find the message they want anymore. I hear, “stuff just gets lost on the forum” now that the thread length is growing and topics are generally off-topic and meandering. People are getting lost and giving up - so just hitting reply to whatever thread was last.
It’s like a tipping point in messiness. Since the few people who used this feature kept things roughly organised, the others could too. But now, its like when the dishes pile up in the sink, and nobody wants to start cleaning up. They just add to the pile.
This flexiblity between self-organising and structure was one of the key features that lead to me to choose Discourse, but it’s currently lost .
At this stage, I’d love it any of the suggestions here were implemented. The marginal difference in wording or UI placement is small compared to the fact without any way to remind my users to keep things on-topic, my forum is turning into a few, long, mixed up threads.
You guys are good at shipping and evolving quickly. So, you can always ship the drop-down and fix the wording or placement later right? 
I am a fan of @DeanMarkTaylor’s proposal for
Not sure when we’ll get to it. You should train your users to use the link button visible on every post, as in:
I want to link this topic… to a new topic I am about to create
Currently, the t key does not act as “Reply as a new topic”.
Some of advanced users keep asking me how they should reply as a new topic? They liked the feature a lot.
Yes it does…
But you have to use j or k to select the post you want to reply as a new topic from first.