Two things: (1) the ability to manage webcam displays in the group so you can see all participants in a meeting. (2) the ability for the presentor or leader who is sharing a screen to monitor what is being displayed as well as continue to see the participants.
Participant icons for those not on video are now on the top, which lowers the tiles of those on camera so I am always looking down. Sometimes they pop to the side, which decreases the size of the video tiles. The circles are also larger. I'd like the icons on the bottom so I am looking closer to the direction of the camera. I don't see this option. I was advised "focus" option moves them to the bottom, but is only available in screen sharing mode. Those not on video should not be the priority or take up real estate closest to the top of the screen where cameras are located.
To make Teams an efficient tool in any meeting and in classes in a school or university environment, these both features are essential. Starting from number 1 and may latter be added number 2.
Carol Bordignon commented
For item #2..... There is another idea on this (with more votes), please vote here: https://microsoftteams.uservoice.com/forums/555103-public/suggestions/37950907-ability-to-see-the-participant-list-while-sharing