This depends on how long your vacation is, and on what type of ticket you have. With an annual pass, it's worth it. But to pay to add it on to a multi-day ticket, or if you only have time to visit three parks, then it's questionable whether it's worth it. On my last trip it actually worked out well because the day I went there, I was feeling tired and a bit under the weather, so that fact that there was less to do and less ground to cover, made it easier to have a slower, less strenuous day there without feeling like I was missing anything that would have been important to me.
The first one that comes to mind is the tram tour, even though it was too short and it needed more points of interest. I would rather that they would have expanded it to make it more interesting, instead of getting rid of it.
I'm not vegan or even vegetarian, but a couple of years ago I really enjoyed the meatless spaghetti dish at 50s Prime Time. It had no cheese; it was spaghetti, tomato sauce, and some type of vegetable protein instead of meatballs. I haven't seen this dish recently on their adult menu, but it was one of my all time favorite meals at WDW.