McDonalds food (excluding fries, ice creams and shakes) has been a joke for a long time now. When, to their credit, they tried to launch a new line of "adult burgers," they failed.
The only thing McDonald's gives to Disney (well, other than money, obviously!) is a venue to offer "collectable" drink glasses and toys for new movies. I know people who buy the happy meals just for the toys, and throw away the so-called food. I'll bet you know people like that, too! Outside the parks, McDonalds makes the most sense to partner with Disney, because there are more McDonalds than any other restaurant nationwide. Yeah, there are lots of fast food venues with better food, including Wendys, What-a-Burger and Back Yard Burger, to name a few, but they can't match the number of restaurants on a nationwide basis.
I hate seeing the golden arches anywhere inside the parks, especially the Magic Kingdom. EPCOT has always had corporate sponsors, so it is a little easier to take seeing a "sponsored by General Motors" over there, but even that detracts from the "escape to another world" we pay so dearly for on our WDW vacations. I would love to see the McDonalds fries disappear from the Magic Kingdom. They are fine for Downtown Disney, if that is what people want.