I, being a developer, would like to contribute, by developing something for a thirdparty site, that requires some changes, but cannot afford to buy the customizations here.
If I were allowed to post/use the community forums on XenForo, I would be able to contribute, without having to buy the "rather pricey" XenForo license, esp. since I do not intent to use it (as a community forum), but only as a test/developer setup.
With the current "model", you are effectively limiting collaboration/contribution to take place between verified customers.
I propose a more "community like" model, where users can register as developers, and gain limited access to the forums where developers thrive.
This way, XenForo would be able to benefit (get - possibly free - additions) from a wider community, than only those running major sites (which do not, neccesarily, have any reason to publish local changes/customizations back to the XenForo community).
Just my 2 cents.