Increasing the size of the court isn’t a slippery slope to somehow making justices elected by states/districts. It’s not like as soon as you get too many justices it turns into a legislature.
The interesting differences between the legislative and judicial branch is not the number of people (moreover, the Supreme Court is not exactly the entirety of the federal judicial branch).
The interesting differences between the legislative and judicial branch is not the number of people (moreover, the Supreme Court is not exactly the entirety of the federal judicial branch).