At this time, the tables in the Tomorrowland Terrace are pre-assigned and guests are not permitted to stand at the rail anymore.
So, if you happen to get a table at/near the rail, the view is good.
But, many tables offer only a partially-blocked limited view.
I would not be happy with one of those.
Starting Oct. 1, 2016, they will be offering Dessert Party guests the opportunity
to view Wishes from the open Hub area in front of the castle (one of the areas previously used for FP+ Wishes viewing.)
That would be the option I'd choose for, by far, the best viewing angle from a "dessert party."