Amjith Ramanujam is a senior software engineer at Netflix. His team is responsible for keeping Netflix services running in the face of extreme adversity. In other words, his team is in charge of doing regional failover.
In his spare time he writes modern CLI tools. He is the creator of pgcli and mycli.
You should say hi to him on twitter.
You're right. It is possible to achieve the same results as fish by tweaking the config or installing a plugin for zsh. Which is fine, but the point I'm trying to make is in order to make those features readily accessible they should be shipped as default not enabled via a config file or through some extension.