LQT is going to be converted to Flow; we just need to talk some more about how and when. Thanks for nudging about it. :)
Converting a wiki talk page into Flow is really just asking for trouble. As WhatamIdoing says, there's no reasonable way to parse wikitext edits as discrete messages. We talked about a few different schemes for making it work, including the one that WhatamIdoing mentioned, and they all basically amount to creating sad Frankenstein monsters that are neither talk page conversations or Flow discussions.
That being said -- talk page conversations are an important part of the history of a wiki, and old conversations should never be thrown away, or put out of reach. In fact, one of my biggest problems with the sad-Frankenstein conversion ideas was that they would break the links in Contributions, which would make it harder to see what an editor has done and said on the wiki.
My current thinking about old wiki talk page conversations is that it's more respectful to move the existing talk page conversations to an archive page, and include a clearly visible link to the archive on the Flow board. This is common practice for old talk page conversations anyway -- going into an archive doesn't mean that they're forgotten. (We're starting to work on search for Flow boards -- I don't know if it makes sense to search a Flow board and a talk page archive using the same tool, but we do have the responsibility to figure out how to keep talk page archives at least as as easily searchable as they currently are.)
However -- on the day that a Flow board takes the place of an active talk page, there will be a moment when a current talk page discussion will need to pause and restart as a Flow conversation. That moment will be irritating for everyone. It's not the end of the world, obviously, and worse things happen at sea, but it will be an annoyance that we have to take seriously as we plan that process.