This makes no sense, since you are the only person who can know, why you would minimize an app. I do believe there is at least one reason to minimize an app which is checking information or performing an operation on application cover.
That would increase the amount of swipes needed to open an app, when having one app on focus. I also think it is unnecessary to make all the current Sailfish users adapt to new ways of navigating the interface, unless it improves the workflow. After all, minimizing an app is only one gesture new users have to learn and for that reason, it doesn’t affect the learning curve more than slightly.