I love where Office 365 groups is heading. It would be great to have a couple more features though.
Shared Contacts - would be great for groups that would automatically be updated and augmented into the group members personal contacts so they could show up on phones.
Planner Tasks - Would be great to have the option to automatically have my assigned tasks augment into my personal tasks.
Dependent Tasks - Would be great to have the ability to have dependent tasks in the planner to easier be able to see which tasks need to be completed first to move forward.