The instant Pittman Jr. went that early in the second round every single receiver shot up draft boards. Hamler went ahead of Claypool and he was a borderline second-round player. They had to take a wide receiver at that point if they wanted one because there would be a pretty steep drop by the time their next pick comes around.
Claypool adds some much needed size and speed to this offense. Also, with a likely chance JuJu isn't re-sign, we have an investment in the position. Teams need to be four deep at receiver.
Dobbins will be a good player, but is he a special running back? No. He'll do great in the Ravens system. Anyone would.