Are there license restrictions or insurance pricing there to keep new riders off of high powered motorcycles like the 600s?
I don't think so. When I arrived here I already had a Canadian motorcycle and car licence; I just got a Slovenian car licence automatically, but I had to take a short course to get the motorcycle endorsement. They didn't make me do the classroom part, just the practical part: three hours around the pylons in the parking lot, then three hours on the road with the car following behind, then the test. In retrospect, I'm glad I had to do it. I hadn't been riding for a few years and needed the practice.
New drivers of all ages here have to take a course for a car licence, and a different one for a bike licence. By the time you're finished, you have some experience on city roads and the highway. Then it's up to you to keep out of the way of cars.
Do cars watch out for bikes well?
In Austria and Germany, most drivers are polite and will yield the right of way to you.
In the Balkans (former Yugoslavia, Bulgaria, Romania, etc.) it's like the wild west. You have to assume everybody is out to get you, because some of them really do drive as if they are. It seems that once drivers get the licence, they forget everything they were taught in driving school.