I've worked on these jacks more than I care to say. Between ours and my parents old MH I've seen more than a few failure modes too.
The good news is they're easy to fix and I have a bunch of parts in my own private stock. (Gears, pins, clutches, etc - I don't have a complete new motor) I also keep a rebuilt spare on hand and I have another complete jack for parts.
As to why eadeals pin broke, the Atwood guys I spoke with said they had some manufacturing issues and had seen some breakage issues that shouldn't have happened. The newer parts do seem to be more reliable.
As to the whining, I'm going to say thats the motor. It was suggested to us to put some type of a flap/cover over the motor to help keep any road debris and water from getting to the motor.
As long as it's working now I wouldn't change it. Ours had a slight whine on the first outing this year, I haven't changed it, it no longer whines.
I would, however, maybe suggest keeping a cordless drill with a properly sized socket installed on board just in case you ever need to crank it up. It takes a lot of turns to move it even a little. :B
I really wish these jacks worked 100% correctly 100% of the time. I love the idea of how simple they are, I love how easy they are to work on. I hate the fact I know that.