Tom likely wants to do Zwei!! the original before releasing something he thinks is better and will appeal more on its own. It would mean extra work for Sara, but they're gonna try Dinosaur Resurrection (music embed related) at some point anyway, so perfect practice is perfect. Tancients and zzblue are still working on the Zwei!! (II) translation patches (according to posts on Heroes of Legend from last year), but they might choose to wait until near XSEED's about to release the games in order to not dampen launch sales.
Meanwhile I posted a thread on Marvelous Forums asking for some unique improvements to Xanadu Next ranging from quick to more involved, and which may have already been debated internally. Still no response, even Tom's ignored that part of the forums because of Corpse Party.
Nothing to say about this, unfortunately. It's one of the most easily forgotten Windows Falcom games, probably because it's too similar to the original games for many to care about.