I know I sit quite comfortably in the Mccartney camp - so I admit I may sometimes be biased...
but
I generally love When I'm Sixty Four, and not for the quirky charm it's so famously known for. I honestly believe it fits perfectly in the Sgt Pepper mould. I think, like the White Album that follows, Peppers contains a dark unnerving feel; a disjointed psychedelic presence - which on the surface is colourful and optmistic...but below..is something quite different.
(This may be the same for some - or total nonsense for others)
I Just feel the Beatles captured the psychedelic feel (accidental or purposely) with an obvious sting in the tail. The Edwardian styled suits combined with the eery Victorian-esq museum feel of the album cover is haunting. The four Beatles coldly staring to the audience. If it's a rejoice to the changing times and revolutionary generation, then why are the four Beatles looking so serious & stern?
Songs such as A Day in the life, Being for the Benefit Mr. Kite, She's Leaving Home and even at second glance, Getting Better, all resonate an ironically colourless vibe:
'I used to be cruel to my woman
I beat her and kept her from the
Things that she loved'
The song is of mild hope, although the sour & bitter past is constantly reminded...with even backing harmonies bringing the song back down to a more gritty level:
"A little better all the time" ...."It can't get no worse"
We all agree that Lennon's lead vocal on A Day In The Life is positively chilling. The end Piano chord not only signifies the end of the song, but the album itself. The full package.
I always think it's such a great 'sign of the times' because it's not a bubblegum view on love & peace. It's pretty rational, in terms of humanistic idealism.