What exactly do you mean when you say blurry? This word refers to a specific effect where the image appears out of focus: https://en.wikipedia.org/wiki/Gaussian_blur
Can you take a screen shot when the screen is "blurry" and then share it on the thread?
Is VMware Tools running? What version of Fusion did you upgrade from? As you have upgraded Fusion, it may be worthwhile to re-install VMware Tools on the Guest OS.
There was a known issue with the host GL driver on OS X 10.11, but as you are now running Sierra, this may not apply anymore.
I wonder if the logs indicated anything when the "blurry" issue occurs. For more information, see Collecting diagnostic information for VMware Fusion (1003894).