I attended the opening of the course in July and can confirm it is very short. They are currently missing two holes, that are still part of the construction area, and consequently two of the par 5s have been split in half to generate the 18 holes. Having said that when the two additinal holes are ready the course will still be extremely short.
On the plus side the holes open were very well constructed, the greens already nice and I did enjoy playing. You are right, however, it certainly won't challenge a championship course like La Manga and may well struggle to complete with courses closer to home, like Desert Springs and Valle de Este. I have not challenged them on this so far.
I understood the problem with the length came about from the infamous "rare plant". I was previsouly told this resulted in 150 hectares of land being "set aside"; reducing the build & golf course areas.
I'm sure you are right to be concerned about the lack of pulling power that the course will have on rental potential. Not sure what if anything can be done about it though. In the short term all that can be done is to make the whole package of facilities 5*, if not 6!