"Overhyped" implies that its popularity is not worth its value. It's clear that it has proven its value to a majority of developers working with React. Especially as applications grow larger, I've found that using Redux provides an intuitive pattern for sane state management.
It does have its pain points (verbosity, async actions) but there's a plethora of libraries one could choose from, depending on need and preference. Since the core functions are so simple, they can be adapted as needed - for example, in a recent project I wrote a wrapper (~20 lines) to extend actions and reducers with namespaces.
An additional advantage of Redux, I think, is that it's becoming widely adopted, so when I look at an open-source codebase built on React + Redux, it's so easy to understand the application architecture.