I think it will be called the iPhone 7, there is a slight design change, one of the lower antenna bands have been removed, there will (probably) be no headphone jack, and the possibility of a darker model. If the rumours are true we will see a much bigger camera in the iPhone 7 and a dual camera in the 7 Plus/Pro (depending on what they call it). There is likely to be a bump in storage to 256GB, and there may well be other features that we just don't know about yet. I can see Apple just giving a camera bump and 256GB storage as the only features, after all they want people to upgrade, even the 6S had more features
Live Photos
3D Touch
bump in megapixels to 12
4K Video
So i'm guessing that there will be more to the iPhone 7, that we just don't know yet, maybe more enhancements to 3D Touch? Waterproofing?