Earlier quoted context omitted.
Can't pgbouncer/pgpool2 solve query redirection? I don't understand the desire for all-in-one solutions.
That desire comes from three places: 1. Minimize cognitive load by minimizing the number of things you have to learn. 2. Minimize deployment complexity and dependencies. 3. Complexity is just evil I'm general. Linear increases in complexity result in exponential increases in bugs, vulnerabilities, and failure modes. It's just combinatorics.
I understand where you are coming from, but having this kind of multi-server-who-is-master knowledge baked into Postgres itself will surely take another couple of releases, if it will be included at all.
Probably BDR (bi-directional replication, master-master like logical replication) will be there first, but whether the question is whether it will help a lot for local scale-out workloads (as opposed to glueing two datacenters together and allow transactions on both sides).