Additional features I would like to see
A way for teachers to create units with specific vocabulary required for their coures.
A way for teachers to assign students speaking/pronunciation practice where students have to create a recording of their voices pronouncing words that the teacher has selected.
Timed competitive games that two students in the classroom can play with each other on their devices.
A feature where students can submit short writing responses to the teacher at the end of the assignment using words and pictures from the assignment.
The features you're looking for are useful for classroom teachers, but they won't fit into what Duolingo is doing; Duolingo is designed for independent learning. You can do all of those things on your school's VLE, though (assuming your school has one).
The timed games between students are 100% confirmed not happening. Luis (Duolingo CEO) said this on an external site, but I'e lost the link. They were a part of Duolingo for a while, but were removed.