Create Private Channels for Private Teams
We need a mechanism to allow for a private channel on a private team. As it stands now, my department that is across multiple states would have access to all channels if I make the Team Private. However, if I make the Team Public and select channels to be private, then anyone in our organization could join the team and it would require us to be very sensitive around privatizing channels.
Thus if I can make a Team Private (i.e. my Finance and Accounting Team) and then could also create Private Channels (i.e. Payroll for a specific region) it would keep the membership narrow for the team and the ability to further narrow the membership for the sensitive channel.
What you describe is how it works now. You can create a Private Team (ie specify only those people or groups that should have access to the Team) and you can create Private Channels within the Private Team for the specific subsets of users and topics.