Will all due respect, what are the odds that a single guy has "insights into Flux pitfalls" that the gigantic creator of React, that is deploying the tech for billions of people, has missed?
Flux, as prescribed by Facebook, involves a couple singletons and implementing an action requires coordinated changes across 3-4 files. Many people find this undesirable.
The important part about the pattern is the unidirectional data flow, which limits the amount of code you have to search through in order to track down a bug. How to go about making this happen varies and there are quite a few 'Flux' libraries bouncing around the React ecosystem.
Quite high, actually. Remember this question is motivated by the pitfalls of Angular, which many "single guys" have legitimate architectural criticisms of:
Your reasoning about facebook and React should apply equally well to Angular and google, if it were valid.
The fact is that with complex technology, even very smart, well-funded people routinely miss things and make decisions that turn out to be wrong in retrospect.
That's a reasonable concern if Flux is a framework. But if you watch Facebook's presentations on it, it is not: it's a design pattern. And a very lightweight one. There's a pretty big design space for tradeoffs in it.
