For me, Personally, I don't mind Coby, he's cool.
I think people dislike him because considering we kinda knew him since he was a marine apprenitice, he didn't show potential or special abilities/powers, but now all of a sudden he goes toe-to- toe with characters that worked their asses off to rached the level they are in, so its kinda like coby is "Oda-priviliged" at this point, showing development levels that make no logical sense at all, yeah sure he trained under the hero of the mariens but so did Rob lucci who has mastered his DF and awakened it (can probably ask one of the five elders to train him too) but still was easy work for luffy.
Also, the crying and screaming and naiveness is adding salt on an open wound, at least make him grow in personality/ character as well, it's like a child on steroids, being shoved down our throat by the mangaka, which is an irritating thought by itself.
Anyway, I like the dude, I think we will see more of his character development in the upcoming arcs.