Like you said, it partly depends on the course set-up.
The best way to get a standard for skill is to use the PDGA rating system. You can look at past tournaments at Waterwork and see what scores correspond with which ratings.
I'll give an estimate. 1000 rated golf (better than average pro golfer) on an average setup would shoot around a 50 for an average score. 950 rated golfer (better than average advanced player) would shoot around 55. 900 rated player (upper intermediate player) would shoot around 60.
There are many players who average over 60 at WW that play in disc golf tournaments. There is always a division for everyone. What does change a little is divisional skill. On your average course, pros playing league will average higher scores than in a local tournemant. Usually the bigger tournaments draw the most skilled players.