I decided to look at this when comparing P5 vs P5 with Shawn and Collins. Shawn played better teams, but he also had more players around him than Collins last two games. Regardless, I think you can give Shawn a slight curve here. Both guys played 4 full games against P5 teams this year and it's below:
Shawn
Comp %: 62%
Yards Per Game: 244
Total TDs: 5 (5 passing 0 Rushing)
Turnovers: 10 (7 INTS, 3 Lost Fumbles)
Rush YPG: 29.5
Rush YPA: 3.2
Collins
Comp %: 58%
Yards Per Game: 235
Total TDs: 7 (5 passing 2 Rushing)
Turnovers: 2 (2 INTS, 0 Lost Fumbles)
Rush YPG: 20.5
Rush YPA: 2.3
Overall, neither player was really dynamic this year but Shawn had 2 turnovers for every TD. That is just really bad and there is no way to deny it. Collins didn't light the world on fire either but he protected the ball much better and just appeared to be in better control out there.
All that said, I am bummed to see him go especially if it ended on bad terms. Seemed well-spoken and a good ambassador for TCU Football. I was probably too hard on him this year as the deficiencies on offense weren't the fault of one player--even the QB. If he stuck around I figured he would have had a good shot to start next year.