I'm not sure how representative the final game was (15-15), STL was missing multiple starting OL (Jake Long and Scott Wells).
It was in SEA, so it might have been ugly anyways, but not necessarily THAT ugly. At home, and with Long and Wells in the lineup, he had arguably his best game of the season (26-134 for a 5.2 average).
Without the last game, he is 235 for 958, which is about 4.1 yards per carry. In other words, about the same as fellow class of '14 RBs Lacy and Bernard, and about a half yard better than Le'Veon Bell, I think all RB1s in dynasty. PLODDERS! Without the week 17 outlier, Stacy did measure up pretty well against his peers, even if the fact that he faced more stacked fronts isn't acknowledged.
He didn't play the first month, than the starting QB was injured a few games later. HOU was a strange game in which the game was over by the first half, SEA was in the second month, and while he did run well against them, they gave up the fewest points in the league. Stacy didn't get a TD until the CAR game week 7, and that was receiving. He didn't have a rushing TD until November. From that point, through week 16, he had 7 TDs in the next seven weeks. If the OL is better, and you think Stacy won't be held without a rushing TD until November this season, there could be some upside there.
Other plodders.
Matt Forte - 3.9 and 3.6 first two seasons. Clearly he was just a compiler, and that was all he was ever going to be.
LeSean McCoy - 4.1 as a rookie and 4.2 in his fourth season.
Marshawn Lynch - 4.0, 4.1, 3.8 and 3.5 first four seasons, 4.2 in 2011 and 2013.
Reggie Bush - 3.6, 3.7 and 3.8 first three seasons.
C.J. Spiller - 3.8 as a rookie.
DeAngelo Williams - 4.1 as a rookie.
Ray Rice - 4.2 as a rookie and 4.0 in his third season.
Retired plodders
Emmitt Smith - 3.9 as a rookie, 4.0 and 3.7 in his fifth and seventh seasons. Obvious compiler that would never amount to anything.
Walter Payton - 3.5 as a rookie.
Curtis Martin - 4.0, 3.6, 4.2, 3.5, 4.0 and 3.8 first six seasons.
Ladainian Tomlinson - 3.6 as a rookie and 3.9 in his fourth season.
Jerome Bettis - 3.9 CAREER
Marshall Faulk - 4.1, 3.7, 3.0, 4.0 and 4.1 his first (and only) five seasons in IND. SLUGGARD!
O.J. Simpson - 3.9, 4.1 and 4.1 first three seasons.