If catharsis requires tragedy, does real-life tragedy require time before it can become catharsis?

All Quiet on the Western Front appeared 11 years after the end of WWI, and Catch-22 16 years after WWII. The Things They Carried appeared roughly two decades after Vietnam. But, later this year, we'll see the release of a half-dozen novels that "use 9/11 and its aftermath as central elements of their plot or setting."

Among those novels is the sophomore effort of not only Jonathan Safran Foer, but 21-year old Nick McDonell (Twelve), which raises yet another question. Which matters more: time or age?