I always had a hard time fully rooting for Gibson and there are some good examples as to why already listed. I can forgive a guy for not being the most talented but being undisciplined was a killer with him. Didn't he ruin the 80 yard TD to Amendola vs. SF? Seems like he was always doing that but it might have been due to him playing a position of far too great of responsibility.
As it's also been said, dude's probably a perfect 3rd or 4th receiver. As a 1st or 2nd...? That's above his pay grade as they'd say in the military.
But, I've been very displeased with Pettis so far and I'd have to think real hard whether I'd rather the Rams had Gibson in that role or Pettis right now.