Now thanks to the folks at 9to5Mac, they have managed to get some additional details about the upcoming feature. According to their source, Force Touch for the iPhone will be different from the Apple Watch. Instead of display additional menus and settings, Force Touch will instead be used as shortcuts.
One of the examples includes the Maps application. Pressing on a point of interest on the map could automatically launch turn-by-turn navigations to that particular destination. Another example is a feature taken from the MacBook where Force Touching a link will pull up a preview of the page. It can also be used to pull up definitions when used on a word.
It is also expected that there will be tactile feedback when Force Touch is activated on the phone, and that according to their source, it has been tuned to feel “nice” and “consistent” across the system. In any case take it with a grain of salt for now, but it does sound like a pretty promising feature so hopefully we will learn more about it soon.