Has "JFK" aged well?

I say Yes and No

Yes because:
It's still a beautifully shot film with great acting performances and quotable dialog. It's among the best political Thrillers I've ever seen. It dramatizes America's paranoia and growing distrust in their government in a way that few other films have.

No because:
First, it plays too fast and loose with some of the evidence in the cases against characters like Clay Shaw and David Ferrie. While there's evidence that Shaw lied about working for the CIA and pretty strong circumstantial evidence that Ferrie knew of Oswald even if they weren't associates in 1963, there's little evidence connecting either man to the events in Dallas around the time JFK was killed. Many of the fringe theories raised in the film like Umbrella Man and the Three Tramps have easily been refuted.

Secondly, Jim Garrison was not a hero in real life. Many of the accusations about him coaching or drugging witnesses are true. Garrison's trial against Shaw was a side show and he ignored real potential suspects like Carlos Marcello.

I still find this movie enjoyable from an entertainment standpoint but I wouldn't recommend it to anyone who is looking to learn about the Kennedy Assassination. I'd rather recommend books, both anti-conspiracy and pro-conspiracy, to people interested in learning more about the JFK assassination