this logic is incredibly flawed .. wow
It's not, really.
DWill is very talented and given any form of OL play other than "derp just stand there gaiz" he will gain more yards. The thing is he's a smart, patient runner who wants to let his blocks develop and pick his hole. Behind an OL that is not developing blocks or generating holes this type of runner generates low to no yards per carry because they're stopped in the backfield or pushing just to get back to the line of scrimmage. Add to this that DWill is not as fast as he was as a rookie (who is?) and you have a bad situation for a very talentd RB.
In Barner you have a young guy, very fast, without the patience to let a block develop who runs as hard as he can (which is pretty hard) at the first sliver of daylight he sees. Behind an OL that is not developing blocks and not generating holes this might be the ONLY daylight you see and it must be seized. In this situation the type of runner who is normally flawed by not having patience might be a better choice exactly because of that stylistic difference that we normally consider a flaw.
This may or may not end up being the case depending on how things turn out but the logic in suggesting it MIGHT be the way to do things is not flawed in any way. Especially based on what we've see.
And for the record noone that I see is suggesting that Barner is the better / more talented back. Just that he's the one that might gain the most yards with the poo OL we have.