"Same exact things were said when Benjamin went down last year. "
Not the same thing at all.
Without exception, the recent SB winners have all included stellar secondaries. Considering the rule changes to benefit QBs, exceptional secondaries are a must.
Most importantly, the Panthers were recently always a fantastic DL and LB group. The weakness was the secondary.
Last year, fixing that got them to a SB. Putting that weakness back in place? Significantly alters their shot at going again. I would almost argue that it removes it completely, barring some amazing draft pick out of nowhere filling that gap.
Benjamin being back is going to make a huge difference, but I don't think it is going to come close to making up for the loss in total. Great offenses win in the regular season, but we have plenty recently that were all-everything and couldn't win it all in the playoffs.
You need a good to great secondary to have a shot to win it all, and the cats just took a big hit on that front.