Because of the drastic increase to the of Wacom stylus pressure levels in recent versions of Wacom tablets, an important adjustment needs to be made in the PREFERENCES panel of 3D Coat, regarding the pressure sensitivity.
Go to Preferences >Tablet Library
This option let you select input used by “3DCoat”. Switch between two tablet libraries: “WinTab” and “Tablet PC”.
Currently “3DCoat” uses “WinTab” which will work only if you will install Wacom “WinTab” driver.
When using “Tablet PC” library which should work without additional Wacom “WinTab” driver.
Also remember switching this icon to pen (pressing LMB over the icon)
Tutorial
This old video show how to setup Tablet sensitivity on Preferences