Rivera isn't the reason at all. You can point to plays this year that could have changed the outcome of the game. When you can point out specific plays, you know that it's execution not the coaching staff. I don't understand how people can blatantly ignore that fact.
It would be one thing if you could point out a whole game (excluding the Giants and Broncos game) where the Panthers played piss poor. The difference now is that the team is making plays down the stretch (ex: AE's punt return today).
If not for Rivera going conservative, we could have eeked out a few more wins. You and I both know this. What's funny is that one year ago, Rivera did much of the same. He went conservative while the Panthers held leads during late games, and eventually, it costed us. A few times.
If Rivera changed, or simply altered his late-game plans/playcalling slightly, many of us fans wouldn't be as disappointed. However, seeing loss after loss, week after week due to the same poor, late-game management disappoints fans.