The problem with todo apps for procrastinators is that they forget or procrastinate on using a todo app to assist in their procrastination.
If there were a generic way to unfuck your life on the other side of it, I could see it being wildly popular. Like a linear progression in weights, or a fasting diet, or a spaced repetition scheme, but for unwinding the effects of avoidant behaviours, with progress and results, that would be valuable.
You're also right about todo apps assisting in their procrastination. That's why I kept NowDo so simple, there are no superfluous features to tinker with like labels, due dates, or categories.