My only real criticism of what we have here is that bigger guys who do longer rides should be allowed more suitable bikes. eg, in NSW (also Austalia), learners can ride bikes up to 650cc, provided they fall within the power-weight limits. For example, a F650GS is learner legal in NSW, whereas an RS250 is not. In Victoria, it is the other way around. I know which bike I'd rather my sons were riding when they start to ride...
This is one of the (few) things the NSW Government gets mostly right (they don't take into account the weight of the rider is my only gripe - while I didn't learn in NSW, I can sympathise with other 6'2, 110+kg people who have to tootle around on tiny bikes).
Personally, were I in charge, I'd go a step farther and institute an additional licence class to capture the really high powered racers like GSXR1000s and R1s - to be licenced for one should require further compulsory, certified rider training (although not another test).
(I have the same feelings about SUVs - there should be additional licensing requirements to be able to drive one. It'd also be nice if you could get an additional licence endorsement that allowed you to legally exceed the posted speed limit on the highway by a given amount as well, but I digress...)
The "problem" with litre-class weapons is not so much the ultimate top speed, but how frighteningly quickly you get there. I borrowed a mate's '05 GSXR1000 for a few weeks a while back and decided shortly thereafter that I'd never buy one for day to day riding. I can certainly see the pleasure in track days and twisties (which was all he used it for), but riding one around town - especially in the wet - requires so much concentration it just takes the pleasure out of it. After a couple of days I just started putting it into second or third and treating it like a scooter for general riding around (although that couldn't stop it from being f*cking uncomfortable).
IMHO, the rationale behind tiered licensing is hard to disagree with in the real world and doesn't meaningfully disadvantage anyone (eg: paying an extra, say AU$500 for a "superbike" licence certification pales into insignificance compared to the money that would subsequently be spent on the bike itself, insurance and all the other stuff someone who really, really wanted one would end up springing for). It strikes a fair and reasonable balance between banning the things outright and stopping people who just need their egos caressing, from being a danger to themselves and - more importantly - others.