Star Wars land will be opening in 2019 so if you really want to do that then go for it.
I would rather visit during what might seem to be lighter crowds during construction. My family doesn't perticulatly care for Star Wars so we won't be saving our trip for when that land opens like many other families might. On the other hand, we probably won't visit the year it opens just to avoid the crowds.
It's all up to what you want to get out of your visit.