One task that would be useful to promote to readers is adding Headings. This could be targeted at articles with more than a few paragraphs of content but without sections. It is one of the newbie exercises in EN:Template:Welcome_training, and it is a classic entry level task - no referencing required! Hopefully an android App could prompt people to add some of the obvious headings, on English that would include See Also, External Links and References.
As well as an uncontentious and useful intro to editing, putting articles into sections reduces the risk of edit conflicts - one of our biggest problems for new editors.