(The dismissive word you and Mel are looking for with "Imagine" isn't "messianic" but "pretentious." Of all of Lennon's personal misdeeds, and he had quite a few, that's the least of them.)
As you probably know, in 1968 JLennon did call a meeting of Apple executives and other Beatles to make the important announcement that he was Jesus Christ. This came to him during an LSD trip the night before. Right after the announcment one of the execs abruptly called a lunch break. During his peacenik phase, he most likely saw himself in some kind of messianic role. On the other hand, he was always changing his views so it's kind of hard to tell where his head was at.
During his peacenik phase, he most likely saw himself in some kind of messianic role. On the other hand, he was always changing his views so it's kind of hard to tell where his head was at. 
