Has quantum theory reached a final stopping point?

Determine whether quantum theory has reached a final, complete formulation (a “final stopping point”), or whether further fundamental changes in physical conceptualization are required for it to attain a level of completeness comparable to classical theory.

Background

Writing in 1943, Planck questions the completeness of quantum theory, expressing skepticism that the contemporary framework represents a final endpoint. He suggests that further, not-yet-foreseeable conceptual changes may be necessary for quantum theory to achieve the same degree of perfection as classical physics.