Hi Blizzard,
As a returning WoW player who wants to play on classic with my kids on multiple subscriptions on the same account, I found that the battle net launcher is completely annoying.
I hope you realize that it is multiple subscription payments and that this behavior would not happen with different scenarios.
As someone who is paying for 2 or more subscriptions, I expect as a user to be able to at least connect to my account as many times as I need via the launcher without disconnection especially on the same network!
As a developer of over 20 years and now beyond a technical lead in 2019 it is unacceptable! Especially when a consumer is paying the money for multiple points of access into a system.
You can at least detect the same IP address this day and age and allow multiple computers on the same network with multiple subscriptions to download easily and most importantly login without service interruption.
Currently logging into wow is completely frustrating with the battle net launcher under this scenario.
Have you tried that with eager kids?
Perhaps not - because you would relate and fix if you had… Taking turns is a difficult concept for the young and also more difficult for the old to explain on tech with a limitation such as this…
Please fix!
This is something that should have been fixed in 2018 
at the very least.
Cheers.