Marker, you are not missing a thing. IAD is one of the most time-consuming airports to use. Between the infamous people-movers and the long rides to/from parking it is always wise to add about 20 minutes to your schedule to deal with all the mess. Perhaps the addition of the new parking garage and the new underground links between the concourses will help. I guess we will have to wait until 2015 to find out.
The parking shuttles do drop off departing passengers on the lower (arrival) level. They do this so they can pick up arriving passengers at the same time. Otherwise arriving passengers would have to get their luggage and go upstairs by the check-in counters to get a bus. Or they would have to have the busses drop off on the upper level and then drive all the way around to return to the lower level to get arriving passengers.
I find it pretty easy to get off the bus and come inside to catch an escalator to the upstairs check-in counters. Admittedly, the signage is not very good.
[This message has been edited by geo1004 (edited 07-18-2001).]