Tom:
Oakmont strikes me as having much more risk than Congressional with less water. But then it's generally regarded as a superior course.
I think folks are making too much about the addition of a single par 5, played once a round, changing the dynamic of scoring. Torrey Pines, notably, and Pebble Beach (as it always does) played much more difficult in recent years than Congressional at par 71.
If it's "soft" conditions, OK -- but aren't there reams of weather data for the greater Washington DC-area going back years and years? If, taken in the aggregate, those reveal the likelihood of certain kinds of conditions, shouldn't there be some way to compensate for that re. set-up? It's an honest question.
If Oak Hill doesn't want to be defaced, it should stop hosting major tournaments. These courses know the drill when they invite the USGA to come in and change a course for one week's worth of play.
To me, the fairways at Congressional don't look like they have much roll-out, which lends itself to more aggressive play off the tee, which results in longer drives and shorter approach shots. The greens have some contour, but don't look too problematic for the pros this week. The bunkers look soft and easy to get out of for up-and-downs around the greens.