The island is genrally in excellent shape, though it is true it is quiet at the moment as it is low season and also some cruise ships aren't coming here due to the piers and bureacratic issues rebuilding them. This should be seen as a plus though - the place isn't so crowded and you'll feel less like sheep! The local people are also as friendly as ever and you can get some good deals as they need the business.
Sorry CableCruiser didn't enjoy the lighthouse - did you climb up to the top? Personally, I found it very interesting and it offers great views of the south of the island. I agree the beach is beautiful, they also have a lagoon boat tour included in the entry fee and you can sometimes see crocs.
If anyone would like to see a full review of Punta Sur Park, see the story 'The Original South Park' on this Cozumel travel
It is simply not true that the police will take you to jail for 'any kind of accident'. Although you will be made to pay for any damage if it is your fault. If you rent a car make sure you take full insurance - there are some other Driving Tips on the same website mentioned above too.
I also agree the beaches are in great shape now.