They recently released 3.2.1rc2, and said the release date of 3.2.1 final would depend on the test results from that; they did not give an estimate.Perhaps Alberto or Rebecca (who follow upstream mailing lists) have better guesses about the current state of mind of upstream.
That wouldn't be as useful as it might look: openwalnut have long recommended using their own repository (in a VM if necessary) instead of their Debian-main packages (http://www.openwalnut.org/projects/openwalnut/wiki/Getting_OpenWalnut), and all the other problems that were actually due to openscenegraph changes (as opposed to other issues that would be RC bugs whether or not this transition existed) were fixed (at least upstream) months ago.Also, for the future, question to Niels: we know that multiple versions of the same library are discouraged, but maybe it would be useful in this case to accomodate to the pace of different rdeps?