Dez Bryant, Julio Jones, Antonio Brown, DeAndre Hopkins, Odell Beckham, Jarvis Landry, Demaryius Thomas, AJ Green.
I think those eight are clearly better. Then you have some guys with question marks (age, injuries) or proven it for long enough but are right in there with CJ based on where he is now. Allen Robinson, Jordy Nelson, Larry Fitzgerald, Brandon Marshall, Mike Evans, Rob Gronkowski if you want to count his receiving/TD production only and not even factor in blocking.
Before you laugh at this, just remember, this is the Calvin Johnson of 2015, not the Calvin Johnson from two years ago. I've watched quite a few portions of Lions games this year on Sunday Ticket and was focusing on CJ because he was on my fantasy team. The guy just is no longer the same player. He is double teamed just like all the other players listed here, so if you think teams are putting in gameplans solely to neutralize him at this point in his career, you are mistaking this with what used to happen.
One thing I've noticed, too, is that the Lions are absolute masters of garbage yardage. With the game being close, they are so often shutdown, but Stafford gets so many yards when they are way behind and give 3-4 drives in prevent defense mode. Yes, you could say that about any team, but my eyes tell me that CJ is even less effective than his numbers indicate because he is so often shut down when defenses are in their normal mode.