The biggest problem with Redux is its complexity. I have seen first hand how Redux scales in large web applications and it sucks. Ask anyone who works at Atlassian and worked on the new Jira, they had to basically break each part of the app up into micro-applications with their own stores because a single-store in Redux for large scale applications does not scale. The navigation sidebar is its own damn React app with Redux store to get around the limitations of a massive store.

If you're looking for a Redux alternative, look no further than RxJS. You get all of the power of Redux without the complex concepts to learn. The Aurelia Store plugin is a great example of using RxJS for state management (it also works with Redux dev tools). A lot of Angular developers will also tell you they use RxJS for state and attest how great it is.

I have seen way too many sloppy poorly performing applications using Redux to know that it is its own worse enemy. The complexity makes for a terrible result in many developer hands.