The thing is, all buzz has been positive. The Trailer they showed at ComicCon was well received. The folks who saw it to for Toy development were impressed, there hasn't been any insider who had any hesitation in praising it, and what's been released was well received, and Action Packed.
If I was to guess, I would have to say it's related to the Man Hours required to produce more of the same.
It's really hard to imagine, that they wouldn't make at
least their $5 Million Investment back with the release of a DVD and then the advertizing revenues from airing it on SyFy. I think A group of Jr. Execs are afraid it will be enough of a hit that they'd be expected by their Seniors to produce more for cheaper and on a schedule, and they can't do it, because they misjudged the Man hours to do the CGI sets.