To me (on the djembe):
Beginner = no sounds, no accompaniments
Intermediate = have the 3 main sounds, can play accompaniments well at slow and average speed
Advanced = can play the accompaniment during a traditional ceremony
I put the focus on the accompaniments and the sounds ie the fundamentals. Knowing 30 rhythms doesn't make you an advanced player. I know guys who played for years, went to Africa, and still can't accompany correctly during a ceremony or even during a session with friends. They are not advanced in my book, although for workshops they'll register as advanced.
Rhythm, parts = KNOW
Playing music = KNOW HOW
If you have the know without the know how, the physical ability to do it, you are not advanced.
But if you register for a workshop, you can go to the advanced levels even if you are a beginner. That's because people confuse knowledge and know-how, real skills, and also because the workshop needs to be filled.
Focus on the solos and the diversity of the rhythms, and you'll stay intermediate or beginner for a long time.
Focus on the sounds and the accompaniment, and you'll be advanced in no time.
Just my opinion, hope it helps.