I think you can make an argument Huntley is better than Brian, but I loved Brian, so I won't make it. But Shelley is a better backup than Brian or Alex ever had. Is that worth anything? It was last year.
The same is not true of Moss. You can make a reasonable argument that Moss is the best Utah RB of all time. Here are Utah's top 10 rushers by career yards:
Eddie Johnson (84-88). 564/3219 (5.7 ypc) with 26 TDs
Tony Lindsay (77-80). 648/2995 (4.6 ypc) with 17 TDs
Devontae Booker (14-15). 560/2773 (5.0 ypc) with 21 TDs
Chris Fuamatu-Ma'afala (95-97). 463/2630 (5.7 ypc) with 15 TDs
Del Rodgers (78-81). 494/2616 (5.3 ypc) with 31 TDs
Juan Johnson (94-97). 582/2601 (4.5 ypc) with 22 TDs
John White (11-12). 534/2560 (4.8 ypc) with 23 TDs
Eddie Lewis (82-85). 379/2179 (5.7 ypc) with 18 TDs
Mike Anderson (98-99). 439/2150 (4.9 ypc) with 22 TDs
Darrell Mack (05-08). 458/2065 (4.5 ypc) with 16 TDs
Right now Moss has 477/2651 (5.6 ypc) with 23 TDs, which would put #4 in yards and tied for #3 in TDs. He only needs about 600 yards to surpass Johnson for #1 in yards, and needs 9 TDs to surpass Rodgers for #1 in TDs. If he edges his YPC up by .1 he'll be tied for first there as well (at least, among the top 10 yardage RBs).
I don't think he's going to have a 1600 yard year and top the single-season rushing record that John White set in 2011 (1519 for White that year), but it's a reasonable argument that he's the best Utah RB of all time. And again, the depth behind him is likely better than it has been in a long while.