Having been involved in Aerial Fire Fighting since it was first bought to Eastern Australia by the (now defunct) NSCA(Vic) what we have now is actually a very good mix of litres-on-fire vs re-attack times. All the current aircraft used (bar the Skycranes) provide a very good mix of being able to fight most types of fires. However as has been stated the huge firestorms that can develop are not really affected by aerial firefighting.
People need to remember that firebombers are not the be all and end all of fire fighting. It is still the guys and girls on the ground that do the majority of fire fighting and are very effective. Helicopters are very good at vital asset protection and for transporting fire attack crews to strategic and tactical locations to conduct bck burns etc and to get into otherwise inaccessible areas in the shortest period of time. Fixed wing (read AT-802's and Dromaders etc) are very good at fire fronts or laying a line of suppressant just in front of the fire to help with stopping it.
However once a fire starts and developes into a firestorm aircraft are essentially useless for fighting the actual fire. Aircraft can't even get near the fire in these circumstances.
Aircraft are best at attacking fires before they develop into full blown bushfires. Spot fires and small outbreaks, where they use their speed and reattack capabilities to the fullest mean they ar emost affective in this area.
As for the skycrane... my own opinion, when you look at the costs and litres per minute on the fire, they are less effective and more expensive than 2 or three medium helo's or three or four light helo's.... I believe these are more a case of the public now expects these helo's here rather than the bodies having theability to get the best bang for the buck. Perception is truth....
The CL-215 was actually bought to Australia by the NSCA(VIC) for a trial one season but it was not suited to out terrain, resources or infrastructure. Better solutions were developed and have proven more effective.
One last thing, you could have 50 helo's and 200 AT802's, but as soon as the fire develops into a bushfire it is the blokes on the ground that are still the most effective means of putting it out. (This is without the problem of being ble to control that many aircraft!!!) Aircraft are a tool to be used and particularly in VIC and SA are used very well. NSW has some way to go and appears to have more political hurdles to jump through as other posters have stated above. (I have no experience in WA)
Cheers
CB