So it would seem...

That Tumblr replies are back in some form? But they're going to be rolled out across the site, and not everyone has them yet? Including me, as of this writing.

Once I do get them, it remains to be seen how, if at all, my use of Tumblr is affected, but I plan to continue cross-posting for the indefinite future -- that wasn't just about the replies thing for me, anyway. But I'm happy for everyone who was missing them.