I wouldnt lump DJ Moore in with those guys. Guy is probably already a top 10 WR right now.
Right this minute, maybe, but he only played 16 games over 2 seasons with Newton. Those 16 games included the first games of Moore's career, and also several where Newton was playing through major career-altering injuries.
Here's how those games played out. The numbers tell it all... he took about half a season to break in and become a regular target, and then went through the normal ups and downs of a rookie receiving more attention from the defense. Then they came back next year and made him the focus of the passing game, but that was the exact same time Newton was playing badly hurt and finally left the lineup.
2018
Sep 9 - 0 targets
Sep 16 - 2 targets, 1 catch, 51 yd, TD
Sep 23 - 2 targets, 1 catch 3 yd
Oct 7 - 4 targets, 4 catches, 49 yd
Oct 14 - 5 targets, 4 catches, 59 yd
Oct 21 - 5 targets, 3 catches, 29 yd
Oct 28 - 6 targets, 5 catches, 90 yd
Nov 4 - 2 targets, 1 catch, 16 yd
Nov 8 - 5 targets, 4 catches, 20 yd
Nov 18 - 8 targets, 7 catches, 157 yd, TD
Nov 25 - 9 targets, 8 catches, 91 yd
Dec 2 - 8 targets, 4 catches, 44 yd
Dec 9 - 8 targets, 5 catches, 67 yd
Dec 17 - 3 targets, 2 catches, 12 yd
2019
Sep 8 - 10 targets, 7 catches, 76 yd
Sep 12 - 14 targets, 9 catches, 89 yd
You can see where this was supposed to go, if things had stuck to the plan. For the first time since he was a rookie/soph, Newton had a legitimate receiver to throw to and the numbers were starting to pile up.
Benjamin could have been a solid WR if not for the knee injury and eating his way out of the league. I think it goes to show you that Carolina tried to compensate for Newton's inaccuracy by drafting tall WRs like Benjamin and Funchess who can make contested catches. Interesting to see what N'Keal Harry does with Newton.
Benjamin was drafted because Carolina got rid of their
entire WR group after 2013. They had 4 WRs who caught passes that year -- Smith, LaFell, Ginn, Hixon -- and all were over 27. They knew going into the following season that they had to draft a WR. As you say, there was a coin flip's chance that Benjamin could become a star, but that went the wrong way after his injuries and attitude kicked in.
It says a lot that after completely cleaning house in 2013, the Panthers had completely cleaned house
again by 2017. The only constant, and the only real quality receiver during that time, was Olsen. Everybody else was a grab-bag of trash being cycled in and out of the lineup. Newton absolutely carried that offense with a
very conservative passing scheme, because they flat-out did not have any talent outside the TEs.