I'm afraid nothing changed here.
This morning I turned the mac pro on and after 30 minutes I got a spinning ball, system freeze with the audio still playing.
But unlike with Yosemite, I had not to push the button to reset it, it did it by itself and sent me to the login page (I don't usually have the login screen, btw).
I logged it and the system became very slow (closing a window was taking about 2 seconds). I was using Chrome when the freeze happened and this is what I found in Console:
Process: WindowServer [218]
Path: /System/Library/PrivateFrameworks/SkyLight.framework/Versions/A/Resources/WindowServer
Identifier: WindowServer
Version: 600.00 (15)
Code Type: X86-64 (Native)
Parent Process: launchd [1]
Responsible: WindowServer [218]
User ID: 88
Date/Time: 2017-05-04 07:47:46.838 +0200
OS Version: Mac OS X 10.12.4 (16E195)
System Integrity Protection: enabled
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Application Specific Information:
Assertion failed: (false && "10 seconds of continuous GPU Driver unreadiness, relaunching WindowServer"), function void IMGGraphicsStackReadinessFailure(), file Server/Windows/Updater.cc, line 2864.