01 ~ I hope that I'm not coming across as disagreeable, Brother Weathers, for I'm a big Fan of yours, but this is the second time I've disagreed with you ~ though only partially so ~ today: I wouldn't go so far as to agree that SpeedBacks are "Plug & Play". I thought it was foolish to let Uncanny Danny go to San Diego and doubly foolish to let Shifty Shane go to New York. They are special Talents who offer far more dynamic Impact than the likes of the estimable White and Bolden, I believe. This is also true of Lewis, and I believe that the Drop Off will be considerable while he's out. Even so, I agree with your Core Point, and have always described HalfBack as coming closer to being easy to replace than any other Position without a substantial Drop Off.
Unfortunately, Mad Bill didn't see fit to develop or retain Depth of Talent at the Position.
Perhaps White'll surprise me. I've always considered him a capable if not spectacular SpeedBack, but perhaps there's more there than I've perceived. God knows: That turned out to be the case with Lewis, himself.
02 ~ And I agree 100% with the Relativity that you described regarding Kong: His loss cost us at least one Championship and maybe two. His Role is essential and the Drop Off behind him is cataclysmic.
That's why I mocked Travis Kelce to us a couple Years ago.