To directly answer the question; it depends on the implementation and/or use-case.
It's not as simple as "more functionality equals greater risk". 2-Factor authentication only ensures that there are at least two channels used as intended and thereby prove that the authentication claim is more than likely correct.
This defeats most of attacks made possible by eavesdropping on a transmission between parties. Assuming the implementation is secure, 2FA tremendously increases security (and to some extent authorization). However, assuming things is always a bad idea, especially in the case of information security.