Only two other Cowboy receivers in NFL history made more receptions in their first three years than Williams, Dez Bryant and Bob Hayes. Only three had more receiving yardage, the two previously mentioned and Drew Pearson.
Of course, that's not as impressive as it sounds given the changes in basic offensive philosophy brought on by many factors that would include the rule changes, increased athleticism, and more complex systems.
If you really wanted to compare WR's from one era to the next, I think you would be better off using stats that compared each in terms of their contribution to their respective teams.
For example, Williams' 133 receptions represents 7.7% of the Cowboys total pass attempts over the previous three seasons. Bob Hay's number of 155 was equal to 13.6% of the Cowboys overall Tarrance Williams only had 5 more receptions than Cole Beasley for that same timer period.
However, the most telling part of Terrance's productivity is his ineffectiveness without Dez Bryant in the lineup.
During the 5 games last year in which Dez was out, Williams averaged 2.6 receptions. Her was almost a total non-factor., In fact hue didn't have a single reception in one of those 5 games in which Dez was not there.
In other words, Williams can be very productive when the defenses focuses on the other side of the line. He is a 2nd option kind of receiver and those type can never be the #1 guy.