Everything about Graham's 3 years has to be looked at in aggregate of the rest of the offense:
In 2015 he missed 5 games and only put up 2 TDs, so undeniably this was a failure of a year, especially given that the last 8 games is where we went on a tear, and Baldwin scored 8 TDs in the 5 games JG missed. But how much of that came about because Lynch went down injured in week 3. Rawls picked up some of the slack but was also a bit boom and bust with some incredible games and some invisible games too.
2016 is the year that Wilson was injured in week 1, and had undoubtably his worst year as a Seahawk, but Graham put up nearly 1000 yards and 6 TDs, pretty much 25% of our receiving output that season.
2017 was the year of no running backs and arguably Wilson's best year, Graham had a down year in yards but did hit double digit TDs.
I still think it was the right trade at the time, but unfortunately a lot of other things went wrong that negated it.