The dessert plate for the World of Color Dessert Party doesn't really change that much for the holiday version in terms of what you get. The flavor/decoration of some items like the macaron or the mini cheesecake or bundt cake etc. change with the seasons but the general offering is pretty consistent. I know I have photos of the plate somewhere but I can't seem to find them at the moment. But just searching for general WOC dessert party plate pics should give you a good idea. There is quite a bit of stuff on the plate and we usually end up taking leftovers back to the hotel in a box to snack on later.
Honestly, a good part of the "value" of the WOC Dessert Party (for us anyway, though I've seen this sentiment shared many times on this board) is not in the desserts themselves. It's in having a reserved SEAT for the show with a great view. This can be especially advantageous for families with children where regular WOC viewing is a gamble since it's all standing only so if you're not at the front of a section (and even if you are but your kids are still short/younger) it can be hard to see. Heck, even for adults viewing can be challenging depending on your height and who is in front of you (or if someone puts their kid on shoulders because kid can't see etc.).