We’re currently working on defining a compact mode experience. I will post more details when we have more to share.
Overall Teams is not a competitor to Slack or another IRC style app. It is really a replacement for Google Groups.
Slack organized around communication channels not people or groups of people. Integrations connect to channels and conversations not teams of people. Until teams makes visible all of the channels and people regardless of the Teams they are members of, it will continue to be quite different from Slack. I cannot effectively conduct multiple chat conversations at once in Teams because I cannot see conversations without selecting the Team first. So currently I default to group chat and direct chat and lose much of the integration capability of Teams.
Deal breaker missing features so far:
No self messaging
Can't pin a message so it is persistently visible while chatting
Can't pin files so they are persistently visible while chatting
No checklists in a channel
no / (or escape character) integrations (have to move to an app)
No real organized help files or access inline from chat (e.g. /help convert to team, /help message self) Should also autocomplete after finding the syntax.
No editable Status if you have a bounce notification on your email. (huge to optimize comms flow)