Eh, the Coleman drop issue was always overstated. From what I can find, he had eight drops over 19 career games. He was 53rd in drop rate in 2016 and 40th in drops in 2017 (couldn't find drop rate rank for that year). Callaway is already at six in six games, which is second in the NFL (and third in drop rate).
And we should probably also consider that Coleman's catchable target rate was almost ten percent lower than Callaway's has been. Callaway has the benefit of far better QB play and accuracy and has somehow managed to do far less than what Coleman did with worse quarterbacking. That, to me, is a huge red flag.
Finally, I'll add that, for the talk of Coleman not creating separation, his average yards of separation from the closest defender from 2017 is virtually identical to Callaway's this year, 1.21 for Coleman and 1.24 for Callaway. Creating separation was not Coleman's issue. His issue was between the ears. Seems pretty much the same for Callaway, although we already knew that coming in given all of his issues.
Not trying to defend Coleman, though, so much as point out how much worse Callaway has been.