Let me throw my 2 cents in...
Those that don't think coaching makes a difference need look no further than the 2012 New Orleans Saints. Sure, there is nothing more important than a true franchise QB, but coaching comes in at #2.
My complaints with Rivera are a little different than Rayzor's, and there are 3 principal problems that make me think he's in over his head:
1) Rivera coaches scared. From not letting Medlock try an end of half FG because Ron thought it would hurt his confidence, to not going for it on 4th and 1 even when you're down big and have nothing to lose (see last game vs NO in 2011), ron consistently tries to take the easy way out. He loves to talk about guys needing to make plays, but you have to give them the opportunity first. If you don't show confidence in your players, they are not likely to play with confidence.
2) Ron's lack of judgement this year in not reeling in Chud in week 4 or 5 when we still had a chance to make something of 2012 really bothered me. It was obvious to every thinking person that Chud's offense wasn't working, but it took Hurney getting fired before Ron did anything.
3) Ron has been very hesitant to pull underperforming players. We put up with almost a full year of Fua starting at the nose last year when he was being outperformed by the other guys on the roster. He finally goes out hurt and suddenly our defense looked legit. Fast forward to this year and only putting Luke in at MLB once Beason's injuries finally got the best of him. Everyone could see that Jon was playing poorly, but Ron did nothing until there was no choice. Same with Nakamura. Same with Norman.
He'll have my full support to start 2013, but in my opinion, we're going to be disappointed.
I'll toss in a couple cents as well, and I think your post sums up the common concerns that most have with Rivera.
1. Coaching scared - I agree that Rivera had his fair share of WTF moments where he could have tried to step on the opposing team's throat instead of trying not to lose, BUT many people look at decisions made earlier in the season when our roster problems weren't quite as clear with the hindsight we have now. Looking back at our kicker situation shows that we might as well have had Charlie Brown out there, and if your kicker is one of the worst in the business then I know I'd sure as hell have to put more thought into what would be a normal kicking situation for normal kickers, which is sadly not the case for us. And as far as giving players opportunities goes, that's what practice is for...this isn't the JV team, it's a multi-gazillion dollar business. And anyone who criticizes the punt against ATL can kick rocks because that decision played out perfectly, we just had abysmal defensive execution between the likes of Nakamura and Norman afterwards. Which leads me to your third point.
3. Pulling players - So, its the beginning of the season and you have an unproven rookie who's played average at OLB and a previously dominant MLB who you just gave a massive payday and has recovered from an injury. Four games Beason played...FAR from unreasonable considering the circumstances. And everyone knew that our secondary was a HUGE question mark before the season started. If you have to start a late round rookie DB and a previous backup JAG FS, then you know you have slim pickings to begin with. Pretty tough to tell a player to sit on the bench when you look to replace him and think "ooooo yeaahhh all those other guys suck too". Did that end up being the right move to bench both of them, I'd say yes, but I can't blame Rivera for having faith that his rookie could develop over the season or that a player from a previous team can adjust to a different scheme. And, I think it is worth mentioning that Rivera wasn't always forgiving for under-performance. Joe Adams fumbles, Joe Adams gets benched. lol
2. Not Reeling in Chud - This is what I think plagues most casual fans. How on Earth does anyone have any clue what was said between Rivera, Chud, Hurney, and JR? You make the wild assumption that Chud is sitting up in the booth barking the plays into Rivera's ear while Ron passively replies "...ok, whatever you say, just don't beat me after the game like last time please...". The fact is, that as fans, we have NO CLUE about 99% of the things that are discussed around here, yet some people on here talk like they're some kind of inside reporter who's actually BFF's with the entire coaching staff. Do I hate the read-option with every fiber of my being? Yes. Can I tell exactly who to put the blame on? Hell no, and we may have just watched our read-option worries walk right out the door earlier this week. Who really knows?? Well, I know who doesn't: the people who talk and complain like they actually do know what's going on.
BONUS THOUGHTS (YAY!):
A - How many times near the end of games were we yelling at the TV, "Why are you calling loose coverage?? The defense is giving up 15 yards every play!!"? My opinion on the defensive playcalling was very negative until I saw that Norman got benched. Then I realized how many times I saw Norman 18 yards deep just trying to keep his receiver in front of him, and I asked myself, "Was it Rivera playing scared, or was it Norman?" Because after Norman got benched, those occasions dropped drastically. (BTW I'm not a Norman hater, just my observations).
B - I've seen player development also mentioned in this thread as a negative with Rivera. Well, for those of you who have those doubts, I'd like to introduce you to Greg Hardy. Any description aside from "breakout year" for him is unacceptable, and I give some credit to the coaching staff for unleashing The Kraken.
TL;DR (probably for most of you lol)
Is Rivera a great coach? No. Is he retarded? No. As fans, all we can do is watch, and hope to God that the team we're rooting for knows what they're doing. So sit back, take the razorblade away from your wrists, relax, and quit pretending like you actually know what is going on inside the organization of the soon-to-be Super Bowl Champion Carolina Panthers.