Ability to set Notification Settings for All Channels in a Team
Instead of having to go into each individual channel to turn on the notification setting, in the team settings there should be an option on channel settings. When you go into the this there should be a list of all the channels with a toggle to turn the notifications on or off for the listed channels, and at the top of this list there should be an option to turn notifications on or off for all channels.
Make it happen Microsoft. Channel notification settings should be ON by default.