I agree that transferring Amex to BW @ 1:1 is a horrible value! I find a BW point to be worth half a US cent, so DC's ratio is OK.
BTW, last I checked, any BW member can transfer any number of points into any other member's account by filling out & signing a form, then faxing it to BW. NO FEE
& NO need to tie it to a specific reservation, as Marriott requires & Hyatt used to require.