Don't know how I did not see this post earlier.
I 100% completely agree that the difficulty between Professional and World Class is too great. World Class in this version is a complete joke. Teams rated in the low 80's or higher is where the problem is. The AI just moves too fast. Period. I have posted about this numerous times and many others have the same sentiment.
I don't know why EA feels the need to not address this. As of Jan. 13. playing on WC difficulty is still broke. They need to either slow down the AI movements and make it so that when they change direction it is NOT at the same super speed as the previous direction (totally defying the laws of physics and making it extremely hard to anticipate their movements) OR they need to stop having the AI make defensive tackles 100% of the time no matter the angle and no matter the distance. I prefer both tweaks, but could accept at least one as a solution.