Which direction to choose for developing a mobile application with api VKontakte?

Question

Mobile development

Hello, I am participating in the mobile application contest from VKontakte. I want to ask what application with integration in VKontakte will be interesting and in demand.
To participate in the competition, the following set of topics is proposed (you can offer your own)
- Conducting live broadcasts from mobile devices.
- Management of VKontakte administered communities.
- Manage photos VKontakte and synchronize them with the gallery of mobile devices.
- Marketplace based on the VKontakte Goods service.
- View videos VKontakte: catalogue, recommendations, playlists, search.
- Interaction with communities and VKontakte events.
- Editing of videos and their publication in VKontakte.
- VKontakte document management with the ability to conveniently preview files (for example, for reading books).

Answer 1

As an administrator of several communities, I simply cannot find services for administering my communities through the phone.