There is a nut that attaches the fuel sensor to the tank and the stock piece is plastic and prone to breaking. I replaced the nut on my bike with one from California Cycleworks.
This aluminum fuel sender nut sits at the top of the sender unit. Note: You will need to remove the pins from the electrical connector on the sender unit to install the nut.
As for the minorly exposed wire, it's still like that in the tank. I never did anything to it. So far, so good after five years and thousands of miles.
The low fuel light works, but I don't put much faith in it. Not sure if that was related to the broken wire problem or not. Because the Monster gets good gas mileage and my riding companions always have to fill up long before I'm low, I haven't tested it much. In any event, I go by the trip meter.