Critiquing helps the artist improve their future works and get feedback. To critique, it involves analyzing the artwork properly and give feedback to the artist.
After Lennon's death the idea of reunion practically vanished.
Still, Paul McCartney, Star and Harrison got together during their work on "Free as a Bird" (which included the vocals of the late Lennon) for "Anthology 1", released in 1995, and for "Real Love" for "Anthology" 2 ”from 1996.