It would be great to have a built-in library of assets where you can:
1- add/buy UI kits and all sorts of elements to your library with cloud syncing or only offline use capabilities
2 - share your work on Behance or Dribbble and for each thumbs-up or like you have a point which you can spend on the online library to purchase new elements
3 - it is necessary that we can add our own elements from the computer with certain formats and it can recognize those and enable user to upload his own graphical resources into his account (make it also public or private for others) and access it on all devices

you always talk about reducing friction, now we have to browse dribbble and Behance for ideas and other marketplaces like materialup for shopping or getting free stuff, if you could aggregate those in one place and make them accessible, easily downloadable and deployable it would be an ocean of new opportunities and already made kits ready for use in new projects which can save design and research and download time.
I hope to see a very very powerful search function for that library which can index icons and pictures for easy finding, like iconfinder or pinterest.