But catches aren't the only important metric. Targets count, too, as well s drops, fumbles, and separation. The others you mention might all be superior to Coleman in all four categories. We've seen Coleman fumble, get boxed out by smaller cornerbacks, mysteriously not jump for balls, have balls hit his head, and, most of all, not give Allen anything to throw to except back shoulder. I can't remember any fades, which were supposed to be one of two throws he is good at, although that might not be his fault.
I don't mean to condemn him; I like his body control, size, and RAC ability. But I don't think he's shown himself to be a featured receiver, much like Gabe Davis. As others have said, his best role might be as a big slot receiver spelling Shakir. A valuable depth player, but no more than that.