The Marshmallow release of TouchWiz (can we still call it that?) introduces a new settings option to enable 'Condensed Mode', which effectively increases the DPI of the device to get more information on screen, something that could previously only be achieved with root access.
It's not entirely clear whether the feature is undergoing testing or whether it's not intended for public consumption (it works beautifully), but for some reason it can't be accessed via the regular settings menu. The quickest way to get to the option is to download a tool such as Density Menu from the Play Store and then use the launcher icon.
We've tested the change on the Galaxy S7 Edge and it makes a huge difference to the device, with the 5.5" screen feeling much better utilised.
Give it a go and let us know how you get on!