Rolling Stone and a slew of other publications named her album as one of the best of all-time. It's her subsequent releases that weren't acclaimed. Also, she put two songs on Pitchfork's '80s list. She had her fair share of acclaim.
Her debut (music and voice) was acclaimed. Check the receipts.
I know.. but if you put her in comparison to Madonna in terms of critical acclaim she falls short.
But in real life Whitney is 1000 times more respected than Madonna and it happens with a lot of other artists.