I kept Double Fantasy in the intro because it won the Grammy (which it would not have if he hadn't been killed) and it was his last record and associated with his death.  It's true that both POB and Imagine were critically acclaimed (and, at the time, Double Fantasy was universally panned) but you may or may not have been around for the "songs addition" debate to the intro (everyone adding their favorite Lennon song; I believe we've reached a consensus that despite all his great songs, the global impact of "Imagine" and "Give Peace" cannot be matched by "Instant Karma" or "Tight Ass"  I'm just trying to keep what is supposed to be an *overview* of an incredible, diverse career from getting bogged down.  I did like your suggestion to remove the family/sons bit from the intro, which I did.  I don't want to crowd this article up so much that it becomes tedious to read.  That includes the inclusion of the not-yet made movie "Nowhere Boy"  there are over 20 movies about Lennon (and Imagine #2 which was technically "by" him) but since we don't (and shouldn't) list them all, we're not going to start with that one.  I know you weren't the one who put in the movie info.   

 Lennon was named "an icon of the 20th Century" (which is more impressive than "a cultural icon"), but I can't find the reference for it just yet.