Without reading through the thread (cbf) I might state my thoughts which probably would've been covered before.
Insofar we can already see Australia has a problem with spin bowling, something people knew would come when Warne and, later on, MacGill would reitre.
We've been lucky in that in the past couple of decades as we've had the two best ever spin bowlers playing at the same time in Warne and Murali, plus Kumble not far behind these two. When you throw in the likes of Mushtaq, Harby, and MacGill, this era of cricket has possibly had the strongest spin bowling stock of all time.
However, this has lead to a complicated problem, not unlike the one created by Gilchrist, in that the current level of spin bowlers lifted the standard and expectations of spin bowling beyond what it ever was before. So now, when the greats retire and the next guys to step aren't immediately as good a bit of panic occurs, which is happening right now in Australia.
I think we, perhaps, need to lower our expectations in general in the coming years in the absence of guys like Warne and Kumble, because while guys like Mendis, Chawla and Mishra have talent and will probably move up to the class of the aforementioned greats later on, the next few years could quite well be painful for a lot of countries in regards to spin bowling, in that most spinners will be little more than adequate at test level, like Vettori, Panesar and Harris.
Basically, I think the quality level of spin bowling will drop below what it was when Warne, Kumble and Murali were knocking about at the height of their powers, but hopefully stay above what it was pre-1990.
Australia's spinning stocks can probably be summed up in one frequently used CW word - dire.
Casson, Heal, Hauritz, Cullen, Doherty, Krejza and Bailey, plus White, O'Brien and Smith. Hardly names to strike fear into the opposition, and all guilty of being incredibly mediocre either now or in the past. However, I think there's at least something there, in terms of talent and ability, that could be turned into at least a test standard spin bowler.
I think the key is persistence and faith.
Doing this by either by creating more spin friendly tracks at home for domestic games, by more coaching, or (hopefully) more A tours to the subcontinent and in general. The situation where Casson went to being the first choice spinner after Stuey's retirement to being dropped back into the wilderness and faith shown in someone considerably worse (White) and someone who is also probably not as good (Krejza) sends a poor message, not only to world cricket, but the rest of the spinners in Australia from First Class to backyard cricket level.
So, spin bowling is one area where Australia have a problem. A second, lesser, problem is that of the wicket-keeper.
For a while there, Gilcrhist averaged an amazing 60 at number 7 for Australia. While that inevitably lowered, I think one thing that can be agreed on is that Gilchrist was a true great, and easily the best keeper-batsman Australia has ever had. While I disagree with the statements that Gilchrist started a trend that the rest of the world has been trying to emulate in terms of wicket-keepers who can score as many runs as he did, effectively being as good as the top 6 batsmen above him, he did do something relatively new in that role in that he was able to successfully counter attack and save an innings, or play an explosive innings that would take the game away from the opposition. THIS is the main problem Australia will face, in that there will be a long time before someone of Gilchrists class will come about again, who can do what he did. Ronchi is trying to be that, but he never will IMO as he simply isn't that good (that's not to say he is a bad glovemen; simply that his batting will never be at the level of Gilchrists, and I very much doubt he'd average over 35 in tests).
Haddin is easily the best choice in the moment. He is a pretty darn fine batsman in his own right, and definitely class with the gloves, but I don't think he can play the type of innings Gilchrist did.
The keeping reserves after Haddin aren't quite there yet, as most of them are young, and some still establishing themselves. The likes of Paine and Wade are good prospects for the future in terms of being keeper-batsmen, while Ronchi is probably second in line now, with Manou probably being the best pure gloveman of the lot (I would personally like to see Paine develop his game and be the one to succeed Haddin).
Basically, Australia will need to accept that it will be a long time before another Warne or Gilchrist comes along for them, and even longer for them to be around at the same time.
The other departments - batsmen and pace bowlers, which usually make up 9 of the 11 players in the side, continues to be ridiculously strong.
At the top of the order there are three test class openers in Hayden, Jaques and Katich, with Katich (obviously) able to be a middle order bat as well, since he is indeed a manufactured opener. In reserve are guys like experienced Chris Rogers (much better than his debut suggests), fast maturing and talented Shaun Marsh.
When you throw in experienced middle order types like Brad Hodge, David Hussey, Marcus North, Adam Voges and Dominic Thornely it looks even better. Then there's the up and comers like Travis Birt, George Bailey, Luke Pomersbach, Callum Ferguson, Phil Hughes, Theo Doropoulos, Ryan Broad and Peter Forrest. Not to mention 3 guys in or around the test team - Andrew Symonds, Cameron White and Shane Watson.
The seam bowling stocks are just as good, if not better.
For some reason the poor showing from Siddle in his only test has some people thinking Australia's reserve bowlers aren't as good as they seem, which is obviously untrue. Siddles selection was pretty poor for mine, as I rate a few seam bowlers ahead of him, as do most people. Not to say he's a bad bowler - definitely one to watch for the future.
The seam reserves look like this: Ashley Noffke, Doug Bollinger, Ben Hilfenhaus, Steve Magoffin, Brett Geeves, Shaun Tait and Peter Siddle, with countless other guys who aren't quite up to standard at the moment, or are not too consistent (Edmonson, Harris, Cleary etc).
Most of those guys would be welcomed into some of the test sides around the world with open arms. In fact, you could probably form a test side from those players that would match it with the best and beat the rest.
The end result? Australia won't be quite as dominant as they were a couple of years ago. I don't think we'll be seeing 5-0 Ashes or as many series clean sweeps, but it's not like Australia will suddenly start getting trounced. Simply, I think there will be more 1 or 2-0 series wins with draws becoming much, much more common for the Aussies.