I have no interest in returning to any programming model that fundamentally revolves around complex sync-up code (also, yes we "tried" this aplenty long before

I have no interest in returning to any programming model that fundamentally revolves around complex sync-up code (also, yes we "tried" this aplenty long before KVO/bindings). As I mentioned in my previous post, I felt KVO was a really interesting design path to be sure, but I agree with you it had its fair share of issues. That being said, observer patterns are just incremental improvements on this. Conceptually its still the same: figuring out ways of getting different parts of a system to eventually "settle" on the same value. Sure, strict typing and whatnot can make this safer, but its ultimately a lot of code that has no real connection to the actual problem your program is trying to solve. Personally I find immutable everything types (through persistent data structures) combined with immediate mode programming for rendering has more or less taken away the cognitive overhead I used to have around this set of "problems". You have a model, that can lead to a new model in the future. You then have a render function that is a function of this model. Its completely deterministic, there is only one path things can go down, you can grab the state of your program at any time and keep re-rendering it to figure out whats going on -- there's no "implicit" conglomeration of state through the value of all the free variables in your program at any particular point in time and their knowledge of each other. If I were to return to iOS programming today, I'd probably give React Native a stab. To me tomorrow land is being able to change code and see it live update without recompile or provisioning profiles or what have you.