Ride is very subjective obviously. I would think that you can feel the difference on the same road if you switch between the extremes. Sounds like ECO goes for smooth and sport will be stiffer. You should be able to feel a difference. I have adjustable shocks on my jeep and if I go from one to seven I can feel a difference for sure but if I go from 1 to 3 I can't tell any difference. Even at that, the difference isn't huge. However, the softer setting (1) is nice for long drives but it I have any weight in it I can feel it bouncing around a bit more, stiffening up the shocks helps control that.
I would be surprised if the CCD made a MASSIVE difference between what setting is set. At the end of the day, the expedition is a big truck designed to tow a heavy load, so it is going to NOT have a buttery smooth ride like a town car or luxury suv. Especially, with 22's. I switched from 17's to 15's on my jeep and that made a huge difference in smoothing out the ride. I personally like the feel of the 18's on my expedition.
Not that it makes a big impact to this discussion but my expedition handled 15 bags of 80# concrete in the back like a champ the other day. I thought that was pretty impressive for an IRS suspension SUV. I didn't even have to lay any seats down. It still rode good too. I do wish there were an air leveling option for the expedition, that weight did make it squat a little but not as bad as I expected.