I have 32gb 5S, and I'm already running out of space (5.7gb remaining)... I can't imagine living with 16gb.
However, plenty of people seem to be fine with 16gb... Most iPhones around me are 16gb, and they just get by without any major issues. It all comes down to number of apps, number of music files and pictures stored on the phone. And they all seem to find right balance between all of them.
As for thinness of phones.... I really don't care as long as they are not an inch thick. I am amazed by how thin 6's are when I hold them, but they don't feel as grippy as previous versions. I guess one day we will see phones become literally paper-thin.
However, plenty of people seem to be fine with 16gb... Most iPhones around me are 16gb, and they just get by without any major issues. It all comes down to number of apps, number of music files and pictures stored on the phone. And they all seem to find right balance between all of them.
As for thinness of phones.... I really don't care as long as they are not an inch thick. I am amazed by how thin 6's are when I hold them, but they don't feel as grippy as previous versions. I guess one day we will see phones become literally paper-thin.