There's no real reason to expect that it wouldn't make it in. Squeeze was just promoted to Stable, so Wheezy should remain unfrozen for months to come. That's ample time to bring in guile-2.0 during the normal migration of packages from Unstable to Testing.

This isn't exactly the right place to ask this sort of questions. Why not email your distro's guile maintainer? Or open a bug report. Or just search for an already existing discussion on this topic on Debian's usual maintainer communication channels.

If the author thinks others might be interested in the answer, this is exactly the right place for this type of question. Sure, it's not going to get upvoted to the top of the page, but it's the type of constructive question and answer that belongs near the bottom of a comment thread. Both Debian & Guile are interesting to hackers, and there would be a large overlap between the type of hackers interested in Debian and the type of hackers interested in Guile.

You could make the same argument for Fedora, OpenSUSE, Ubuntu and others and I don't think it would be a good idea to have threads for all of those in this discussion.