First of all, the spin on the NHTSA results is amazing. A Google news search shows these three articles near the top:
Smart Fortwo crash test results a mixed bag MotorTrend Magazine
Smart ranks low on US crash test Detroit Free Press
Smart car aces US crash test despite door opening Reuters
The one thing most of these articles miss is a discussion of how the fortwo compares with its closest competitors. Without an idea of its relative safety compared with its closest peers, the writers are just spinning the results IMO.
Secondly, I wouldn't be surprised if smart issues some type of 'fix' for the door opening problem, if it's more than a fluke. Look at the results of the 2008 Mitsubishi Lancer which received a similar warning for the rear door. Mitsu issued a fix and the car was reevaluated with better results. Same kind of thing could happen if it's a real issue.
Overall, I was satisfied with the results. As others have said, no one would argue that a fortwo is the safest car on the road, rather it is very safe for its size. After scanning through the results for 2-door cars (or 4 if a coupe isn't available) like the Focus, Lancer, Aveo, Accent, Cooper, Cobalt, etc., the smart results look to be in line with what you would reasonably expect from a vehicle smaller than these nearest competitors.
Parting thought: If a car that's half the size of a Cobalt should get twice the fuel economy, shouldn't a car twice the size of a fortwo be twice as safe (or at least max out the scale). What!? You mean there aren't any? What kind of pathetic engineering is going into these other cars? A car that big should protect its occupants from small thermonuclear detonations and meteor impacts! ;)