I think they still have the classes but there is not much savings these days. Years ago, we saved almost 50% on our tickets. Now, you might save a few bucks. Not worth giving up park time for us.
Now I really enjoyed the YES class and wasn't doing it just for the discount. But now when it will cost me so much MORE than the alternative it's no longer something we'll be doing. Would I pay the $36 or so for just the class (as an add-on to an annual pass)? Yeah, I might. But right now the economics make that class awfully expensive.
We saved HALF by getting YES tickets in 2012. And while DD & DW enjoyed the class immensely, there's no flexibility. You have to choose your dates & pay in full up front. That's doable when you save half. The current savings isn't even 10% IIRC. Not worth it.
unfortunately, the price increases make this option not as attractive as it once was.... a pp noted some good reasons... it's less flexible and simple to sign up and get them, and the benefits aren't as good anymore.