Generally when someone calls someone “shallow” or “surface-y,” it is considered an insult. The idea is that someone lacks any depth mentally, spiritually or experientially and is incredibly superficial.
However, that insult did not stop Bobbie Houston using that on Oprah:
Grateful to have sat under this woman’s wisdom and insight tonight. Miss Oprah! Her faith isn’t far from the surface. #sydney
Source: Bobbie Houston, Instagram, https://www.instagram.com/p/_MPk49IYxJ/, 12/12/2015. (Accessed 13/12/2015.)