Error propagation

Hi,

i'd like to ask you if is expected on next future to have error propagation (when REQUEST fail or FAILURE). At the moment i'm using following pattern:

```
dispatch(rsaa_action())
.then(response => {
if(response.error) /* ...A... */
else /* ...B... */
})
```
but i think it could be better if the error were propagated in order to use normal pattern:

```
dispatch(rsaa_action())
.then(response => /* ...A... */)
.catch(err => /* ...B...*/)
```

Please, could you let me know something about?
Did i fell in a concept mistake?

My best,
Niccolò