What you should be looking for is an interior arrangement (floor plan) and a collection of features that your family can live with. Then you try to find it in good condition.
The collection of problems on the Minnie Winnie sound minor and easy to fix. They could be difference in age, or indicative of lax maintenance. The three year newer Fleetwood could have the same problems three years down the road without regular and proper maintenance (batteries in particular don't last much longer than that, thus the short warranties).
My experience in ten years with two local RV clubs, folks more often end up trading to different RVs because the RV didn't fit their needs, not because it had things that needed to be maintained. The first two you find don't represent everything out there that is available.
The older Minnie Winnie is likely more expensive than the newer Jamboree because the Minnie Winnie is considerably upscale (Minnie more closely competed with Jamboree). The floor is set well about the chassis frame rails to give it a basement, and most of the utilities are in this basement, which is likely heated (it was in the 2004 model year).
Depreciation from this point? Depreciation is typically a constant fraction of value per year, so for same current value, the curves should closely match. 2002-2005 you are already past the big part of depreciation.
When I was shopping, I passed on the Minnie Winnie (=Sundancer) 30V because I thought it was too heavy for the chassis and I don't like to see LPG appliances in a slide out. We found a Spirit (=Minnie) 29B which was a similar floorpan with almost as much room, but a few hundred pounds lighter. We did not expect to make use of the extended season the Minnie Winnie basement provides.
