Just being able to view performed activities in different ways in the mobile app would be an enhancement. I would like to have weekly and monthly summary with details, being able to dig into details
I agree with adding the calendar to the android mobile app. There is a widget listing your workouts, which means absolutely nothing if you can't see them on the calendar or in context to a training plan.
I agree this is pretty poor, but here's a workaround (I use an iPhone). Open you Garmin Calendar in Safari, save the webpage to your homescreen as an icon. Drag the icon next to your Garmin app icon (I have them in the same folder with Strava). Job done. Ok, you have to come out of the app to look at your calendar but it works and will suffice whilst we wait for Garmin to add the calendar to the app.
Dave