I have been saying this since this version came out back in September. World Class is broke. AI moves / switches direction too UNREALISTCALLY fast and their defenders ALWAYS catch up you, even if your player with the ball has 99 pace. And the tackling ..., way way too over powered. They make 110% of EVERY tackle in their defensive zone. Another issue with WC difficulty is the lack of 2nd chance shots. Every on target shot you take that is either blocked by their goalie or defender ALWAYS ends up rebounding directly back to one of their players.
Roughly 7 months later, the difficulty has not changed. My current team has a 92 rank and there are times when playing a match against a 83 ranked 7 chem team can be much more difficult than a match against a 90 rated 33 chem team. The inconsistent difficulty (what should be based on their ranking) is frustrating. You never know how much of a gain they are going to add to all of the AI's sliders.