I agree with your impressions of Cozumel. My favorite place in all of Mexico and the Carib. We've been to most of them but always return to Cozumel. East Island is just as you say, wild and beautiful.
Loved Cozumel - horseback riding on a Cruise Day Excursion.
Understood from our Mayan guide that the island is almost wholly owned by a Mexican rancher who lost all his cattle in the Gilbert hurricane. The area was still rather desolate.
Lovely people and great sense of humor.
sp