we were on the dream in Sept. The ship is fine. just big and lots of people. we didnt experience the long lines that others complained about, but I am sure it can be long at times.
you will love the ports.
cozumel check out chanancanob park, it is beautiful, you can swim, snorkel, walk and see ruins.
at roatan, take the skylift to the beach, It is one of the prettiest beaches around.
at costa maya go to mahalajau... it is a little village about 3 miles from the port. It is getting more touristy but is still like being in mexico.
at belize, take the tender and go shopping and then return to the boat.
Dont believe everything you read, you will have a great time