FF possible? Yes, but not with current NX lenses because of electronic contact and dimension make it impossible for lens to access FF sensor dimension.
if want to use current NX lenses, only capable crop size is 1.3x or APS-H size sensor or even bigger with 1.18x.
if Samsung go FF, they need new FF NX lens lineup. I think still possible to use APS-C NX lens in crop mode but adapter is needed.
for me APS-H or 1.18x is better because no need for adapter and difference in picture quality with FF is only 1/3 stop with field coverage increased about half of APS-C or additional 4/3 sensor size which is very useful and significant. especially if gap in picture quality between APS-C and FF is closing. the difference is pixel size capacity of APS-H due to sensor size. with digital processing playing significant role now, APS-H picture quality can surprise us and rival FF. of course, big question is cost. if FF cost 2k, for APS-H to sell well, price should be 1.3k.