Everything I'm hearing is valid, based upon the arguments presented.  Everything depends upon Planetside's eventual audience.  Boxed software always (including Modo) comes from those in a certain group interested in selling to a specific client base.  Based upon the gradation from Terragen .9x to Terragen 2, this isn't Terragen .9x anymore and I see a major shift in quality as well as potential audience.  
Of course, this is really a call for Planetside marketing to make, of which I have nothing to say.  So, I'll reiterate that as a consumer I'd prefer an offical package.