"Redux is a simple library" woah woah stop right there. How is this:

    const handlers = {
      [CREATE_NOTE]: (state, action) => { ... },
      // ... a thousand more of this
    }

simple? This looks horrible. Every time you want to work on code that modifies data, you have to switch to the one file where you keep all the data-modifying functions? Seriously?!

Freezer https://github.com/arqex/freezer is a much, much better experience. You just shove immutable objects down the component tree, and they just come with methods that modify "them" (by actually changing the data tree). It has an event system as well for when you actually want to centralize actions. Works great with Polymer, by the way!