I would vote "YES".
That is, Yes to an "ace-neutral" count. But keep a side-count of Aces. Since an Ace-10 still equals 21 in this game (and in most places, all Diamonds still equals BJ), a deck rich in Ace's is probably advantageous, especially when also Positive.
Further, if one DD's 11, and draws an Ace, One can always surrender.
Some of the "math folk" can hopefully give your post more precise answers to your question.
I played SF21 once as a "ploppy" last year, but plan to "study up" before my next LV trip in Feb. Seems a whole lot like LV Club's Liberal 6D game, which pays 3:2 on all BJ's, but does not have "Surrender after DD" option. Both games are certainly "Fun"...I am not sure either is "SuperFun".
Of interest, at least to me, SF21 has just appeared in Tunica...one table at the Sheraton (a Ceasar's Property). There it is called "Fun 21", and has all of the same rules, the best I can tell. The table is always full, so I have just watched a few hands. They do not have the cute little rule cards available in the corner of the table like LV SF21...I suspect they are offering the game without paying royalties...they have a "cheap" little sign in the right corner anouncing "Fun 21", and another "cheap" placard in the other corner listing the rules. When I say cheap, I mean the type a hardware store would engrave for you for $3.00 + tax.
Certainly, if SF21 stays around permanently, then OCKO's work will likely become the Thorpe of the game. Likewise, if you are a Green Chipper on bj21.com, then Mr. LVBear has some interesting posts on this game.
Good cards, and Super Fun!