Good article - and 'spot' on - if you'll pardon the pun.
Crude oil is 'fungible'. Yes, the yields per barrel for 'lighter products' such as gasoline are higher with the 'light crudes' - but, no, removing sulfur from the crudes is NOT that big a refining issue any longer.
One of our previous associates could expound quite elegantly on that - still miss him. Strokes can be pretty terrible.