Abbey Road is the Jewel in The Beatles Crown ?
Even though it's not my favourite Beatles album , it's pretty much the "Blueprint" for the modern Pop/Rock album ?
Technically Abbey Road is their best album vocally and instrumentally. They sound almost like a classical band on tracks like "Because and parts of the medley. I think they were hitting on something grand with “I Want You (She’s So Heavy) and the Abbey Road Medley both influence on heavy metal and progressive rock respectively. But unfortunately broke up.
To me a huge influence on much of modern rock/pop is Revolver "Rain/Paperback Writer era why? You had Pet Sounds still seeped in Phil Spector Wall Of Sound, Frank Zappa very much a parody of Varesse put into rock music and the unreleased music of the Velvet Underground. Revolver for one it doesn't sound like anything before it and compare it to say Bob Dylan Blonde on Blonde which most of the album is still restricted to established pop styles. Not really on Revolver you have classical Indian "Love You To", avant/Indian "Tomorrow Never Knows" and what is "Eleanor Rigby"? That helped expand on what you can put on the rock canvas.
It's really on "Rain", "Paper Back Writer" and "Tomorrow Never Knows" is where the production and ideas shine through. You have boosted bass and drums right up front, loops, and change of speeds, processed vocals, and automatic double tracking on "Tomorrow Never Knows”. The ideas on that one record is common to what you hear today.
“Paperback Writer” has again that boosted bass sound and some nasty guitar distortion. Then “Rain” the track is vari-speeded to create a dense rock sound a trick that Les Paul did but the Beatles take it to another level on “Rain”. Again the bass and drums are the vital part of the sound right up front but they add something to it by using a backward vocal fade-out to make it trippy. What I am saying is the Beatles were one of the first rock groups to combine close-miking on the drum and a boosted bass sound on the same records. That helped influenced much of what you hear in pop and rock music today.
You can make a case every Beatles album was a progression and it broke some ground.