Not sure I can agree with mixes being too "aggressive" in quad/surround effects, but then again I haven't been listening this way for very long, being new to the quad experience.
But I would always take "aggressive" over the lame and feeble attempts found in other, supposed quad, releases like Lennon's Imagine. The only thing revelatory there was the first non-mono appearance of How Do You Sleep?
Aside from the Fireman releases, I would say Paul's worst was McCartney II.
I started listening to Beatles solo material with the then-current Tug of War. Several years later I started listening to his back catalog and I think the first was this one, Venus and Mars, which I was able to find on an EMI cassette, something very rare at the time.