With all due respect to the hypothetical question you posit here, with my full disclosure that my intention is by no means to denigrate let me ask the rhetorical question if I may: given that Sergeant Pepper is largely regarded by most all legitimate rock 'n' roll historians and critics as the greatest album of all time and largely "perfect," why would anyone even attempt to suggest that one could improve on perfection and or the greatest albums of all time? Why not let "sleeping beauties" lie and appreciate what you've got? :-)
Would "Sgt. Pepper's" be a better album if.....
....."Within You Without You" was dropped from the LP and Side 2 began with either "Penny Lane" or "Strawberry Fields"? If so, which of these would best kick off the second side?