Yes, at the time BOTR was a refreshing change in Paul's musical offerings, and yes, it has not worn as well as a real classic album.
I think a few of the songs you mentioned are indeed lesser by virtue of their quilt part filler material (Vanderbilt, Picasso etc.), yet they are still infectious enough to sing along with.
Some of the songs are very good tho and stand out....Let me Roll It, Now Words, 1985, etc. Really overall the album lacks a continuity but still is a good collection (especially for Paul at that time).
For many there is a nostalgic element to their feelings about it, tending to skew it's worth a bit. Not that I can cast stones about that, us first-gen 60's listeners wallow in nostalgia about the music.