There's one thing you NEED to get out of your head.... a winch =/= a hoist. you will burn out the single holding brake in a winch in short order and the load will fall. Winches are not designed for vertical lifts, hoists are. there also is more than one load-holding brake in a hoist. ... and from what able to see the structure of the roof... the load path will collapse the bottom chord of the gable end... it was never intended to resist a concentrated sideways load.
Agreed! Unless you can locate a hoisting winch that has an independent safety lock system, the brake is inevitably going to fail. The worst case would be when the load is at the second level, and the brake lets go as you are reaching to unload. If someone is anywhere at the ground level, it is not going to be pretty..... The least case scenario is that you will be replacing that nice window on the side of your house as it crashes to the ground....
Sorry to pour cold water on the idea - I always like new engineering problems, but this is a big no no...