I'm certainly not above making mistakes. I don't agree that "generally", female vocalists have lousy material, though, if by "generally" he meant most female vocalists.
I liked B. Howard with A. Shakes, too . . . and Allison Russell when she was with Birds of Chicago and Maya Di Vitry when she was with Stray Birds and Lindsay Lou when she was with the Flatbellys. Is there a theme, here? I just happened to prefer their work with the groups listed for stylistic reasons.
Is Lake Street Dive "popular"? Rachael price is, by any measure a terrific vocalist who started out as a Jazz singer. Their material is a bit too Pop for me, but very well done.
Did anyone mention Marty Stuart ? He certainly qualifies as an excellent front man, but (here we go again) not Rock.
Anyway, I hope you've gotten a few useful suggestions from this thread.