Just changing dynamics in a song (or if you're Mariah Carey or Christina Aguilera, hitting 6 octaves in every song) doesn't really do anything in terms of the song itself.
Agreed: Mariah Carey and Christina Aguilera are irritating vocal peacocks with no sense of taste or discretion.
Whitney Houston, however, was actually a legitimately great singer
You old fuck.
Christina, in her later, fatter years, has toned it down a bit (her back to basics stuff).
Could be she gets winded and/or hungry during songs. She has a great voice as well in my opinion.
But whatever Fork says. She wasn't born 100 years ago, so she sucks.