Excellent albums on your list there. McCartney's Ram is a lesser-known favorite of mine as well, as is Van's Street Choir. Distilling my favorite studio releases down to a dozen would a tough task. Listing only live albums (as I did earlier) is a lot easier. ....I'll give it some thought.
Janis Joplin
Joni Mitchell
Linda Ronstadt
Natalie Merchant
And what about Blind Faith and Cream's Disreali Gears?
Also left out ole Joe Cocker w/ his first album as well as Traffic w/ Winwood, Capaldi and Mason
In retrospect there was so from about 67-72/73 its hard to single out. What about and being quite serious: Jefferson Airplane w/ Crown of Creation (and overlooking Gracie who by now is probably a great grandmother) and feel free to laugh.
I can see your thinking here. It's difficult to make judgements on the best of album(s) of a artist/band when many of their best stuff is spread out over numerous albums.