Hi Ross,
I left my boat in one year. Fortunately, it was a mild winter with only two snows. I was down every weekend checking on the boat.
If the boat is in the water unless you are hooked up to electricity and have a charger hooked up to your batteries, you have to be concerned with the batteries running down and making your bilge pumps useless as they would have no power to run them if needed.
You still have to be concerned if there is any water in the water jackets of the motor. Boat in or out of the water and motor not winterized.
If it snows the boat will fill with snow and then the snow will probably harden and block your scuppers, keeping any melting snow from draining. The added weight of any accumulated snow will lower the boat in the water.
Keeping the boat in the water will also enhance the occurance of the hull blistering. The fiberglass will be water saturated.
True, people do leave their boats in for the winter. But I think for the peace of mind, unless you will be going to the boat VERY often take it out and avoid a worrysome winter.
Just my opinion.