was it criticized on any grounds?
No.
We Belong Together
"We Belong Together" became a "career re-defining" song for Carey, at a point when many critics had considered her career over. 
who was mariah carey song we belong together about A woman's desperation for her former lover to return. who composed it? Mariah Carey, Jermaine Dupri, Manuel Seal and Johntá Austin. was it part of any album? Yes, The Emancipation of Mimi.
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We Belong Together [SEP] Critical reception
"We Belong Together" became a "career re-defining" song for Carey, at a point when many critics had considered her career over. Unlike most of Carey's recent singles at that time, "We Belong Together" received generally positive reviews from critics, most of whom hailed the song as her "return to form", following reviews for "Charmbracelet" (2002), that suggested Carey had lost her signature vocal range and power. Sal Cinquemani of "Slant Magazine" wrote "the... diva [keeps] cool with breathy, rapid-fire verses until the final full strong-voiced climax that... proves that 'The Voice' has indeed returned." Additionally, he said that "The song is as 'innovative' as Mariah has been in years." Other critics commended Carey on her novel singing style which, according to Kelefa Sanneh of "The New York Times", gave the song its propulsion, writing "This style is part of the reason why she has been able to turn a ballad into a summer smash.