It would be good to be able to click on a calendar button on the left hand side to get a view of the Office 365 groups calendar as you would in the calendar app. Good for being able to look and get a glimpse of what is coming up with the group. At the moment I have to go back to the calendar to look at it.

I want to have separate top-level windows for each person I'm chatting with, rather than tabs.

My team has some users on Linux, and one benefit Slack has is a Linux client. Without a Linux client on Microsoft Teams, some orgs may have to turn away in favor of Slack so everyone can participate without keeping a browser open all the time.

Ability to see who is currently in a channel. Hipchat and Slack have this feature

If a conversation is started in one channel but gains importance to the point where the conversation deserves its own channel. Or a conversation was started in the wrong channel and needs to be moved

Please integrate more with Planner (hopefully soon with Kanban and timeline visualisation channels for tasks) and/or with sharepoint web parts that do this, so all tasks linked in one place. And Outlook as well (for calendar and emails pertinent to chats and tasks). Until then in effect Teams is yet just another tool to use that is not completely integrated for communication + coordination.

When renaming a Team Channel, the associated Sharepoint folder continues with it's previous name. This could lead to confusion.

Would love to have a Calendar to allow those in the same team to view each other's availability and whereabouts. Would make it a lot easier to create appointments/meetings.

The calendar could be a tab in a channel (so then you could have multiple calendars in one team) or could be an icon on the left app bar, instead of "Meetings" which is helpful to no one.

Could also be helpful to add a way for us to add a SharePoint Team calendar.

It's very confusing to new users that there is a difference between replying to an existing conversation and starting a new one within a channel. This is a visual thing as much as anything else. The 'reply' buttons are not naturally attractive if you just want to start typing a message. There should be a logical gap between the bottom of a conversation and 'start a new conversation'. 'Start a new conversation' needs to be separated visually, as if it's a second order command rather than a first order...reply.

It would be nice to integrate public Skype (not Skype for Business) into Teams. I am able to chat with Skype for business users within my organization but when working with external clients I still have to go back to public Skype. If I could even just simply chat and call with Skype users as well that would allow me to use Teams as my sole communication platform.

Mobile working, Asynchronous working of teams is a common phenomena. Read receipts let us know if the message has been seen, so we know it can be acted on. Critical when large numbers of the team are mainly mobile workers.

Every time you create a task in planner via Microsoft Teams and assign it to someone in your organisation/team it would be nice to see that task in outlook as well. I want to know and to be alerted that I have a task assigned to me without having to lon on to Microsoft Teams.
It would be great to have a place to see how many tasks have been created in a team/channel and the status of each one.

Notifications built into the OS (which all apps I've seen use other than Outlook and now Teams) are more functional and allow for more user control. Most importantly, they honor Do Not Disturb settings, which is critical.

Currently files are downloaded only to the DOWNLOAD folder. Allow a save as function / select download location.

Once I enabled guest access on the tenant I can enable guest access to a team, but I can't give guest access to a single channel. There should be a way to do this as I will now need to create a guest team and an internal team when I share teams with customers.