Not sure what any of this has to do with Cee Lo Green's version of Imagine, but I'll chip in anyway...
I wouldn't say, as someone did earlier in this thread, that John "abandoned" Julian between 69 and 79. John did spend time with Julian when he and Yoko were still living in the UK - John, Yoko, Julian and Kyoko went on holiday to Scotland in June 69 ...
(the choice of outfit could certainly count as cruelty to children though
Julian also spent time at Tittenhurst with J+Y, and he features in the Imagine film.
Obviously, after J+Y left for the States the time with Julian was cut to irregular visits, but there were still letters and calls across the Atlantic between the two (some of the letters and gifts John sent to Julian ended up in the excellent White Feather exhibition that Julian put together in Liverpool.) And Julian had a cameo appearance on the Walls and Bridges LP. So I certainly wouldn't say that John abandoned Julian altogether.
However, on the other side of the coin, someone earlier in the thread was defending John's poor treatment of Julian because John was in the biggest band in the world and there were a lot of demands on his time. Well, Macca never seemed to have had a problem with spending time with his step-daughter while he was still in the Beatles or with his own kids once they arrived in the '70s. Obviously, it's a different scenario because Paul was in a stable relationship with Linda while John and Cynthia had split up, and Paul had had the benefit of having the presence of a loving father himself, (unlike John), but I still do think that John could, and should, have made more effort with his first son.
So it's a complex picture - Lennon certainly wasn't a saint or an angel, but he wasn't a complete and utter b*stard either.
I've always wondered if I would even have liked John if I ever had the chance to spend time with him, but it still doesn't detract from the fact that he made some amazing music - and I count Imagine among that (just to keep this thread on topic slightly!). And he did indeed spend a fair bit of his own time in the late 60s/early 70s campaigning for a more peaceful world, which was no bad thing.
This sort of thread would probably never take off with Macca or Ringo as subjects - George, perhaps, was complex enough to promote this sort of discussion, and John definitely was, so we should be grateful at least that he has given us something to talk about!!