Lost in all of those statistics may be the level of talent and expectation for each of those teams. I'd think the Barves streak may indeed be the most "disappointing", despite having a title thrown in there...
Agree about the level of talent. Frankly, the Nationals' level of talent surpasses the Chiefs in their respective sports. The chiefs have an above average player at the most important position, where as the Nationals have two "once in a generation" talents and a HoFer in their prime. On top of that, they've had a player in the top 5 of MVP voting in 3 of the last 4 seasons (four out of four for the Cy Young).