Christina’s issue, from this humble commentator, is that she just doesn’t seem to have found her own thing. She clearly has the best voice of the crowd she came up with.
Adele writes her own material, and I saw her sing those big songs with nothing but an acoustic guitar accompaniment. And they sounded great.
Don’t mistake my comments as panegyric for Christina over Adele. Adele’s strength is the soul she puts into her music. Christina just has the gift of power in her voice. She needs better songwriters.