the US system is 100% less dramatic
Very valid point, which I think is the basis for some pilots being pro-NAS (including the big Dick).
I'll attempt an answer, and hope that some others more current can jump in and (politely) help.
The U.S. has a ****eload more infrastructure. I liken it to a full service petrol station, with mechanic attached. In oz, we have a fully automated self serve, with a console operator taking your money. They have a lot more traffic, but 20 times the number of controllers, plus FS, full radar, briefing etc etc. Their system is a lot more labour intensive and less automated. This is a double-edged sword in oz, because TAAATS, a big shiny computer that can do things amazing, requires a lot of prompting. Once your details are in there, it's great. But for you to just pop-up, a controller (who is also controlling, doing Flight Service, and the asistant job) has to basically do a flight plan on his console and enter it into the system for you. As a one-off, that might be OK, but it is very time and attention consuming, and he cannot regulate his workload. If it's a nice day, any number of guys might pop-up in a 10 minute period, and he still has to wear all his other hats, some of which are a higher priority (such as seperating). U.S. controllers don't wear various hats, they are specialised because of the volumes they are working, and have that huge infrastructure to do the other jobs.
Clearances into class C airport don't require flightplans and almost always get approved
Is this now clearer why? The U.S. controller just jots your details on a strip, his co-ordinator starts co-ord, his flight data (assistant) enters data and your in. Some of these tasks are made easier in oz by TAAATS, but you have the hurdle that is step 1 (many-hat-wearing controller manually entering plan) as previously mentioned.
I'm not sure why the aussie system can't work like this
The oz system has been stripped down to save money (FS gone, Data's gone, computerised briefing etc). The controller
cannot just jot details on a piece of paper anymore. In addition (and this is a key point), the U.S. charges differently. Their system is payed for out of consolidated revenue. In oz AsA is run as a "business" which pays a dividend to the govt. This is a crucial factor in much of how the airspace is run. It is essentially a large billing system. This is an aspect of airspace that no-one high up wants mentioned. If they were serious about solving the "GA malaise", this is the aspect they would address.