Pandora is a lot more interesting than Tatooine though.
Plus it'd hardly be the first movie to have all it's sequels set on the same planetary body. We just had the sixth Mission: Impossible movie set on Earth.
None of it's marquee markets (UK, Aus, Japan etc) have opened yet and won't open till September. Remains to be seen how well it will do in those countries but it's a bit soon to completely write it off.
It cannot be denied. The people love sharks.
Well, they love being scared of sharks. Jury is out on whether they want a shark as a roommate or whatever.