Still, if my opinion counts I think SELF-UPDATING MATERIALIZED VIEWS should be the next priority.
https://www.postgresql.org/message-id/flat/20170119213859.GA...
More info in the EDB roadmap: https://wiki.postgresql.org/wiki/EnterpriseDB_database_serve...
Postgres has been amazing in shipping the foundation required to deliver complex feature.. Logical Replication is an example of it, all the piece commited in the last 6y allowed to make this patch achievable.
About raft-based leader-election, I believe the current recommendation is to look at patroni ( https://github.com/zalando/patroni), which has been built for docker and is now being integrated with Kubernetes; however, I don't think there is an inherent limitation that it couldn't be run on bare-metal.
I quite confident that the postgresql from 5y in future will be quite different in term of storage / server topology support. I won't be surprise pg_bouncer capacity to finally make its way to core when we have a coordinator.
Postgres has steady progression (even if not fast enough for some people) but they are moving without compromising robustness of their product for the users.