Fruitcakes are traditionally very dense, so a lot of recipes contain quite a bit of butter. You could try to decrease the amount of butter (perhaps by 1/2 cup) but keep in mind, the texture will definitely change. In my opinion, if you enjoy the cake, follow the formula in the recipe. After all, you probably only eat it once a year, so splurge and enjoy it!
The reason that fruitcake is swaddled in cheesecloth is that the cheesecloth itself is usually soaked in liquor (usually brandy or rum). This evenly distributes the liquid and penetrates slowly into the cake, which is often why fruitcakes are kept so long to "age". You can control the level of moistness in the cake by adding more liquor to the cloth over and over again to let it soak in gradually. Cotton can also be used because the material will allow the cake to breathe. After being wrapped in cheesecloth, it is then wrapped in foil and kept in an airtight container to age in a cool place.