I believe aTc already has a stretch/testing OS image and by the time the Pyra comes out we may be off Jessie. However that version of openMW may be opengl only and needs glshim or some other optimization.
OpenMW need OpenGL. It needs to be built against OSG and QT5 with OpenGL. This is not currently supported by glshim (but I plan to add support for it at some point in the future: need to add PBuffer and PixBuffer support to the glX part).
There are some dependencies that can't be met by Jessie, so no, you can't use these packages right away, regardless of OpenGL.
From a mere packaging point of view, I'd say building a Jessie backport shouldn't bee too complicated. It would require some work, because some of the dependencies need to be backported as well, but at first glance there's nothing blocking a backport.