The 83 percent for Obama is not the problem. The additional 5 percent of registered voters is. They need to see the Obituaries and clean the rolls. Once they do that it should be back to around 100 percent. The reason 83 percent for Obama is not a problem is because DC voted for Obama by even a bigger margin.
Even 100 percent voter registration doesn't pass the smell test. In a clean, free and voluntary system, there are going to be people legally eligible to register to vote but who simply aren't interested. I believe that the national average is something in area of 70 to 80% of potential legal voters registered. Nothing shady about that.
What is shady is registering people, real or imaginary, who you know aren't going to show up to vote (and voting in their absence) thereby increasing the percentage of registered voters close to 100% or beyond.