I would recommend a reservation, just so you don't have to wait in the huge line that those restaurants get. As others have said, you don't have to make it through Disney. In fact, during my trip last month, I called at 4 on the day I wanted to go and they told me they had pretty much everything open that evening! I make a reservation for around 7:30 I think and by the time we got there, there was a long line of people waiting to be seated. Between making the reservation and being Landry's Select Members, we were seated immediately, while the people who were in line directly behind us with a party smaller than ours did not get seated until at least an hour later (we were finished with our meal and working on dessert when they were seated at the table next to us).