I just don't see any reason to replace Haitink's perfect version but others prove me wrong. It is perfect in interpretation, recording, and performance. Moving, elegant, dreamy, longing, monumental...
...My own long time favorite is the Boult stereo version, infinitely more idiomatic than Haitink (who really doesn't "get" Vaughan Williams, - it's an outsider's approach), and Shelia Armstrong & John Carol Case beat everyone else in my judgment (their "Explorers" is just terrific).
I've heard many fine recordings and performances of RVW 1, but none has ever surpassed Boult/Armstrong/Case for me.