And indeed, they need to show some consistency in selection, especially regarding the spin bowlers position. I was always under the impression that Krejza had been selected because he is seen to be an attacking off spin bowler who gets considerably more turn than others who engage in his craft. He is then ruthlessly dropped for returning some bad figures against some of the greatest batsmen in world cricket on a pitch which offered him very little. He still troubled nearly every batsman on show, and yes, he bowled some dross, but he did this when taking those hatfuls of wickets against India too. Either accept this is part and parcel of selecting such a bowler, or don't pick him in the first place. If they want someone to tie up an end, then surely Hauritz should have been selected.
I don't know the actual rationale behind Krejza's selection, so it may have been completely different to the idea which would've been the right one. However, the right idea with Krejza would've been to take him to India, play him, and then not pick him in Australia. At all. His First-Class record shows quite clearly that in Australia he has close to zero chance of any significant success. It's a strategy advocated by one Robert Cribb, who assures us that Krejza can occasionally bowl very well on turning pitches but can also bowl very poorly quite often.
The trouble is that once someone's gotten 12 wickets in a match (even if they have conceded nearly 360 in doing it) no-one is going to understand if he's not picked again. To leave a fingerspinner - any fingerspinner - out at The 'Gabba this season was quite the right decision, because the surface suited seam, seam and more seam and was never going to offer appreciable turn so therefore no matter how attacking a spinner someone is perceived, if they're a fingerspinner they won't get good batsmen out. If picked, Krejza might've expected to have bowled 10-15 overs all game, and this could easily have cost Australia as they'd have been deprived of that vital seam option and would've a) had to bowl lesser seamers like Symonds and b) had to bowl the seamers they did have more and thus tire them out quicker and make them less effective.
If the strategem behind picking Krejza was to do a short-term job in India, it was actually very good selection. However, if it was to have a long-term option who'd play regularly in Australia and elsewhere then it was very poor, because Krejza's First-Class record simply shows quite obviously that that isn't going to happen.
Continuity is ideal in the cases of most players, but fingerspinners are the exception to the rule. If they're to have decent careers, then picking them in every Test is simply not an option. Ashley Giles' case shows all too well what happens when you do that. It might seem un-ideal for the confidence of a player to be constantly in and out of the team but I assure you, it's far more of a dent to a player's confidence to be being constantly belted for stuff like 1-200. Ashley Giles was a very strong player mentally so he could've coped with either scenario, and did with the latter, and thus generally bowled very effectively whenever the pitch allowed him to. And if he'd been afforded the former then he'd now generally be regarded as a fairly respectable bowler rather than the joke so many so wrongly regard him as.
Nathan Hauritz isn't good enough to be an attacking weapon on almost any surface so if Australia did want a defensive option in Australia then he'd be a better pick than Krejza. Personally I'd say that no bowler should ever be picked for Test cricket as a defensive option, any Test bowler has to be able to take wickets in his own right. However, if you wanted a defensive spinner in Australia, the right thing would've been to have picked Hauritz over Krejza the minute you left India. That'd have been good selection, in terms of picking the type of player who can offer something rather than nothing (in that no defence + no attack < defence + no attack, even though neither is a scenario you want for a Test bowler under any circumstance). But can you imagine the outrage if Hauritz should've been picked in preference to Krejza when Krejza's most recent game was his debut?
These trigger happy selectors need to understand that the current Australian side is a work in progress, and that younger and inexperienced players are going to have to be persisted with until it is clear whether they are up to the rigours of Test cricket or not. They need only look at their current opponents to see the effects of this - cricketers such as De Villiers and Steyn who have come through the initial stages of looking ill-equipped for Test cricket and are playing a huge part in the emergence of South Africa as a world class side.
I don't think de Villiers ever looked ill-equipped for Test cricket TBH - I myself thought he looked the part when I first saw him in under-19 cricket in 2003. And certainly in his debut Test series I always thought he retained promise and sure enough in just his 5th Test he made twin scores of over 90.
Steyn's a different matter and was hopelessly below-par in his first 3 Tests but it was a massive error to select him then (there were a good few superior bowlers around at the time) and that was one of a good few factors that led to SA losing that series.