That he was gifted beyond reason goes without saying, and lived an unfortunately tortured life in his middle years (ANOTHER one . . . . . . ).
The two things that stand him apart for me from just about anyone else that stick out:
1) In THE WRECKING CREW, IIRC, maybe I saw it somewhere else, here's all these hard professional session players that had seen and heard almost everything and were rarely impressed by much, was Hal Blaine and Carol Kaye talking about how 'this kid' had come up with all these amazing songs and arrangements, and they were all in as they rarely were on most of the dates they got called for, it was that good.
2) Paul McCartney said they were caught flat-footed and knocked off their game by how amazingly good PET SOUNDS was, and realized they had better get back in the game right now. The result? SGT. PEPPERS LONELY HEARTS CLUB BAND.
IF just these two things don't qualify BW as an almost unearthly talent, I don't know what does.
We will not see his like again.