I know I'm in the minority - maybe I just had a bad experience or something - but I did it once and don't think I'd do it again.
The parade was nice - but we're not really parade people. We only watched it because of the perception that we paid "extra" for it (we're passholders, so it's not like we were able to buy MVMCP in place of a park ticket for the day). Holiday Wishes was also pretty good, but I prefer Wishes. As for the cocoa and cookies - the cocoa was what you can make with hot water and an envelope at home, and nowhere near as good as if you make it with milk like I do. The cookies were like prepackaged sugar cookies you would buy at Walmart, and they had been frozen and (mostly) defrosted. If you think of both of these as being "free", you get exactly what you pay for.
There are other events around the park, dance parties and such, but we didn't really partake in any of those - maybe those would have brought the value of the experience up to the price point.
It sounds to me like your biggest concern is being disappointed you spent the money. Based on my experience and the feelings expressed by everyone else, as well as the enthusiasm that came through in your post, I'd put that risk at no more than 15%, especially if what I've written tempers your expectations just a little.
On the other hand, if you skip it, there's a 100% chance you'll always wonder whether you made a mistake. So from where I sit, the math says do it.