There are large numbers of same same apps out there. To the point when someone shows you a cool one that wants payment, chances are you can find a similar one that is free.

I think personality-tailored apps are going to be the next thing. Apps with features that specifically appeal to micro personality traits. Hyper-niched apps if you will; niche in terms of how they support mixtures of activities dictated by the user's personality.

For example: there are many many to do apps. And they all have slightly different ways to enter, manage, display tasks, and also to enable different amounts of “controlled procrastination” – like a Snooze or Delay Reminder function. They emphasise different aspects of the to-do list domain. One would provide more satisfaction from checking off items. Another may have features to support obsessive categorising. Yet another may encourage putting items off. (Have a look at Behance's Action Method.)

Deliberately designing apps to suit micro personalities traits could be a useful differentiation technique. As opposed to designing apps to some research or focus group derived “requirements”. A variation of this is to build apps that suit a developer's specific individual personality, knowing that there would be could be just enough people like him/her in the world to truly appreciate it out there. This means making the app an intimate part of the developer's daily life. Like making and selling well broken-in shoes and jeans...