Love Myth Busters. One of the issues, and the reasons that roundabouts were tried in some of our subdivisions, was because of accidents--people ran the stop signs. (Still do). With the roundabouts, they didn't go around, but turned Left against the traffic--because it was ....shorter and faster! The other problem we had, was that fire engines, could not get thru the round about. Granted these were much smaller than the ones noted near Anacortes.
The best solution was one taken at the intersection in Panama City and Panama City Beach--very high traffic areas--and the vast majority of traffic was shuttled over the intersection on two levels of elevation--with stop lights at the bottom, for those who wanted to some contrary way. Far more expensive than the roundabout--but handled a far larger volume of traffic with no stops.
I see the bypass, but why not both ways? (again it would be more expensive). There is definitely a learning curve--and I used the Long Beach Calif. roundabout several times daily for many years, but it was the neophyte who caused the problems--or that person who didn't follow the rules...)