Maya was chosen to be the first plugin mainly because we have some old industry friends who are evaluating it for use in some productions, and they use Maya. So, that pushed Rhino, which will be the next plugin, to second priority.
After that will most likely come SketchUp, because we still have some core things (e.g. hair, volumetrics, etc) to implement, before we can really take advantage of the more powerful applications like Cinema, Blender, Houdini. From the archviz side, we also get requests for 3dsmax, so we will have to see how things look, but given that, of these, I have the most experience with Cinema, it is most likely Cinema will come after SketchUp.
However, I should say clearly, that I am just giving you my rationale here, and that we cannot officially commit to a particular order, since factors can change over time — and I never want to encourage people to make choices now, based on future promises.
That said, thanks for your thoughts, they will be valuable to us, in making these types of decisions.