Interesting discussion here with Keith Blount, a few weeks back. Hints that Scrivener iOS is almost feature complete -- and improvements in Scrivener 3 for desktop. Not surprisingly, sync is the major hurdle for Scrivener iOS -- talk here about moving from one device to the other to work on the same writing project.

http://www.macnn.com/articles/16/01/28/the.history.and.the.future.of.software.including.the.much.awaited.ios.scrivener.132221/