I think Gibbs is a great player and will get his touches/TDs. I'd rather look at it as a whole for the RBs as we have 4 solid ones.
Last year we averaged 190 ypg rushing over 10 games with Sims at 492, Gibbs 460, Mason 362, Griffin 229, and Smith 298.
I'd like to see us at at least 240 ypg rushing this year with Sims hopefully coming down a few yards to no more than 400 range and saving himself a bit.
For a full 12-game schedule at the higher rate and keeping the percentages of touches similar (and likely will have some McGowan thrown in), we would end up with Gibbs at around 700, Mason 600, Griffin/Smith around 400-500 range each. Now that would be an awesome quad that saves some bodies by spreading the load. I see Gibbs getting the most receptions out of the backfield as well but Mason and Smith are no slouches there either. If he maintains the 24 receptions/10 games, he'll be at 30 receptions and 300-400 yards this year, so all-purpose over 1,000.
Rushing TDs would love to see a minimum of a 50% increase from 18 to 27. Percentages would give Gibbs 9-10 of those.