Samsung may have to cut two planned features from the final version of the Galaxy S8. The innovative optical fingerprint sensor may be replaced by a traditional one at the back of the unit and the Viv Assistant could be dropped due to legal reasons.
http://www.notebookcheck.net/Samsung-Galaxy-S8-Two-planned-features-might-not-make-it-to-the-final-version.187957.0.html
The fingerprint scanner located at the back would be so uncomfortable. If I have a soft transparent case for that device then I should take it all the time just to scan my finger. That option won't be good.