I'm not sure how much this movie would benefit from 4K, unfortunately. Even aside from the big VFX set-pieces, CGI and digital compositing were integrated in nearly seamless ways throughout the entire film, for little things like changing a detail in the background of a shot or tweaking colors here and there. Most of it was designed not to call attention to itself. The commentaries on the Blu-ray talk about this quite a bit. Although the movie was made before the era of full Digital Intermediates, partial DIs were used for more shots than not. And all of that work would have been done at 2K or less.
As for Atmos, the opening scene and the big climax would certainly take advantage of that, but most of the movie in between is (by design) much more aurally sedate.
