Frankly, I dislike the Sindbad show. Don't hate it, just dislike it. However, I'm in live with the wonderful Islands of Adventure, and even though the new HP island is great, I can't help but think the IoA I once knew is gone forever, now that the focus is always on HP first. An example of this is JP, which lost much of it's ambiance to a great brown castle, whose boat ride's chances of returning are slim to to an ugly bridge, and whose amazing animatronic walkthrough has been overshadowed.
Now, the following comment is not aimed toward anyone personally, but saying something could/will be because you have no proof it isn't won't is the recipe for a conspiracy theory.
I would think, if there were plans for an expansion, we'd see something that would indicate it, like an online survey question, or the slightest in-park hint, much like BG has done. So far I myself have not seen anything like this. So I have to assume it won't happen because, as of now, there's nothing saying it will which I believe is very logical.
As I said before, I would prefer there be no or little expansion, but if it does happen, I will embrace it, because you can't stop something by willing it to happen. I just think it won't. Can you respect that?