When the Freedom debuted on the Today Show they did a great job with the whole show - including Katie Couric at the time - being done from the ship. I remember they showed all the public spaces, had a Manilow concert, etc. Katie even moved the ship under the guidance of Captain Bill.
I think part of the problem with the GMA show is RCI still has crews working on finishing some work on the Oasis. RCI may have placed a lot of limits on what could be shown. Perhaps still catching up on work they couldn't do because of the storms during the crossing? Regardless, the show did little to promote the ship. It could have been shot at the Mall Of America and they would have gotten away with it.