This is going to be a bit of an essay.
I think most of the haters need to look past the player and focus on the tactics. Cooper is copping a lot of flack, however it's easy and popular criticism for those who don't follow the game heavily.
Robbie Deans needs to accept most of the blame for the Wallabies poor showing. He went with the perceived notion that you need to play 'tournament rugby' to win a World Cup. In hindsight it's a call he'd love again, however I can understand why he found it enticing. The last two champions (Eng & SA) have played this style - kick it away; play for field position, errors or penalties. It's bloody dull, but painfully effective if you have the cattle. Besides victory, the other commonality is that both of these teams had >85% goal kickers and, imperatively, the best forward packs. It's not a style of rugby we should have attempted.
To put it into perspective - the English and Saffer packs contained ~5 forwards that would walk into a World XV. Australia has one, and even that's debatable. It's also worth mentioning the only other player who would challenge for a spot never boarded the plane.
FTR last nights front row was the weakest we've fielded all tournament. It's a stretch to say Maafu is international standard. Just on the prop rotation - it's been a disaster. Tighthead and loosehead are specialist positions. Deans elected to play our best available tight head at loosehead and our best loosehead at tighthead (go f-ing figure). Our best prop never got on the plane, whilst our (debatable) next best was completely underdone. I digress.
My criticism of Deans is that he spent four years developing a style of Rugby suited to the cattle at his disposal. Genia, Cooper, Beale and JOC are all once in a generation players. It was no fluke we had beaten the Kiwis in two of our last three, or absolutely dismantled the Saffers at any chance over the past year. Guess who was in the 10 guernsey on all of those occasions?
Deans gave them rein and was rewarded, it's baffling why he pulled them back and reverted to a game plan that would inhibit our best players.
On Quade (again):
I touched on why he wasn't favoured by tactics in my earlier post. Another aspect worth considering is the performance of the man inside him. Genia is such an underrated player and, IMO, far more integral than Quade.
Quade is a front foot fly half. A feature of his game is that he stands quite flat in comparison to most. A dominant pack isn't requisite, however you sure as hell can't do it without quick, clean ball. Quade spends his time in the pocket, ordering Genia and the forwards around, biding his time. He waits for the moment the defence is unsettled, something his flat style allows him to take instantaneous advantage of.
On the other hand Barnes plays off the backfoot, it's characterised by how deep he stands and far more suited to the way Deans envisaged us playing. It's no different to left and right side players in the NRL. Swapping sides, or in this case - depth, can just about turn their worlds upside down.
Back to Genia - no one in world rugby can clear a ball quicker from the ruck than him. It's no different to a quick play the ball in League - the benefits are the same. However, perhaps more importantly, his mere presence creates oodles of time for Cooper. Defence will never rush up on Quade as they're terribly wary of leaving a hole for Genia to scoot through. It's akin to rushing up on Locky on the last tackle.
This World Cup we barely saw any of Genia strengths. Coaches orders saw him keep the ball in the ruck as long as possible, playing for a penalty. As a result of not having the forward fire power, he was harassed all tournament, whilst the opposition had a fair amount of success counter-rucking. With Genia rarely giving clean ball Cooper had no option but to stand deep, abandoning the flat style of play he is accustomed to.
As I have mentioned earlier, Deans had the wrong man at 10 for the style of Rugby he wanted to play. As expected, Barnes was great last night. 'Tournament rugby' suits a player off the back foot such as him.