Ubuntu 16.04 will ship with an option to move the Unity Launcher (dock) to the bottom of the screen.
The feature that allows moving the Unity Launcher / Dash to the bottom of the screen, landed in Ubuntu 16.04 Xenial Xerus (to be released on April 21st) on Friday.
At this point in the Ubuntu 16.04 Xenial Xerus development, the option to move the Unity Launcher to the bottom can only be accessed via gsettings / Dconf Editor (com > canonical > unity > launcher > launcher-position):
I should also mention that since there's still a month until the final Ubuntu 16.04 LTS release, this feature can change!
Below you'll find more screenshots as well as a video demoing the new Unity feature which allows moving the Launcher to the bottom:
(direct video link)