Funny thing is, years ago, when I made my own Post Wilma trip report (from a 02/06 trip) and reported the incredible underwater devastation.....totally nuked came to mind......., the Cozumel mafia on the board almost crucified me ! To me, Cozumel can be divided into two separate time eras, BW (Before Wilma) and AW (After Wilma). I wish I'd been certified sooner than in 2001, so that I could have enjoyed more of the Cozumel BW era.
As far as sparing the far north and far south ends of the island.......some dive ops, especially the cheaper ones, won't take you there due to the extra time/fuel expenses involved, and the northern sites are famous for only being offered by the expensive, boutique dive ops catering to the most advanced/experienced of divers.