Hi there, I seem to have found a solution to this exact problem.
I am running 10.12.2 OS (Sierra) as of today.
I have an Intuos CTL-480 Wacom tablet.
I could not get the device to read, nor the pen to work with the latest driver from the Wacom site (6.3.20-8).
I uninstalled through the Wacom utility and then installed 6.3.20-4 which I found though a google search (I downloaded here, hopefully it doesn't put trash on our machines... https://photo2drive.com/apps/wacom-tablet-driver?platform=hootsuite
After installing and restarting my Mac, the pen still did not work but the device mounted as indicated in the Wacom Desktop Center (a feature that is in the applications in the newly installed Wacom folder). In the Wacom Desktop Center and went into the pen settings (first top left) to configure and instantly the pen came to life! And it is still working so...
Full disclosure: I embarrassingly just updated from 10.4.7 ... or whatever my original 2011 MacBookPro OS was (if it ain't broke don't fix it). My Wacom Tablet and Time Machine stopped working out of nowhere and so had to finally update.
In other words, no Mac expert here and not planning on continuing on this thread, but hope this helps others not to spend many hours on this as I did!