I have to 100% put my weight behind the directional option. Cyclists going against the flow of traffic should always yield to those who choose to go the wrong way.
I understand your point with the hill, but that just gets confusing. Much of the bridge is not an incline, so what do you do then? And many people do not understand the hill rule. In mountain biking, downhill typically yields to uphill, but with other vehicles, the rule seems to vary, based on the country you are in, if one vehicle is pulling a trailer or has better pull-out access, etc. And I never understood the momentum theory. It is easier to pull over and stop when going uphill, at ten MPH, compared to downhill at 20 MPH. The difference in speed more than makes up for the difference in incline.
Anyway, I understand both sides of the argument, but believe the directional rule is the simplest and most logical. And, easier to explain with a brief sign at the beginning of each span...