If you want to have fun with dead island you need a co op player that you play with alot. Playing with random people or solo really isn't fun in that game.
Also the first area is the most enjoyable. After that it is more narrow in focus. Overall the game is big and there is alot to do, but most of it the same thing except replace item x with item y and go get it.
Its a huge miss of an opportunity to tell a good story and make you care about what is going on. But its not goofy enough to go the other route. The most fun you will have is killing zombies in fun ways, but because of that playing co op is the only real way to get satisfaction out of it.