"We are looking to make improvements to the mobile app. We'd love to hear your ideas for making mobile hosting easier!"
Just solve the current technical issues hosts and guests have to deal with daily and you will make hosting, not only mobile, easier.
You will have less people complaining on social medias, less time delay while contacting phone CS, less booking issues to solve and more time for real hosts and guests issues and to educate new hosts.
On the CC we could share experience and create a real community in spite of spending most of the time teaching people about hosting basics.
This is, from my point of view, what most affects brand since month and the Achilles' heel of Airbnb.