As for Magical Mystery Tour: While the Beatles didn't choose the track listing themselves, they evidently approved of it, because they didn't come up with a new track listing when they made the CDs, and all the songs are from the same time period, so that's why I count it as a real album. There are only four new songs on Yellow Submarine, and they're all leftovers, so I don't count that any more than I count Long Tall Sally.
Although A Hard Day's Night does contain more acoustic guitar than the previous records, the previous records do still contain acoustic guitar, and the tracks on A Hard Day's Night are still almost entirely rock and roll. Semi-acoustic rock and roll, yes, but STRUCTURALLY they're still rock and roll. As I've said, this changes suddenly on the next album, where very little of it has the rock and roll structure.
Here's a summary of my theory:
Era 1 : Roots Era : Primarily rock & roll and ballads : PPM, WTB, AHDN
Era 2 : Fast Growth Era : Primarily non-rock & roll, non-ballad, folk- and country-influenced pop and pop rock : BFS, H!, RS
Era 3 : Psychedelic Era : Primarily psychedelic rock : R, SPLHCB, MMT
Era 4 : Splintering Era : Extremely stylistically varied : TB, LIB, AR