I've got a '22 35 ordered. Here's the reasoning; the cost of the 37 package is $5k-ish. I'd rather choose the rims (method) and tires (nittos). You can't tell me that the 37s Ford picked are the best looking for the truck, tires are ok and rims are good, but neither is great looking. I'll take my $5k savings and buy from the entire universe of 37s made for a raptor and still have the 35s.
Not that the stock 37 wheel looks bad by any means, but I will agree with you that you could probably pick a better looking wheel with all of the options out there, but I thought the tires for the 37 Raptor were designed and special for that truck alone and like 10+ lbs. lighter per tire. Kind of a big deal if that is true.
Even if I am wrong about the tire info, everything that combatninja said is true. Ford designed the 37 Raptor to function and fit with 37's. Also, if it ever came down to it, you can void parts of your warranty, or maybe even your whole warranty, if you put 37's on a 35 truck. To give up all that and gamble on your warranty for a $5k savings doesn't make much sense. IMHO the only reason to get a 35 over a 37 is you can't wait almost 12 months for a truck and need get something quicker.