There's actually a lot of debate on this out on the web since I've seen several people note that they're expecting lunch volumes well beyond anything most counter service spots have ever seen...and that said volumes should be an issue for quite some time. i.e. people suggesting they might start lining up at 9am to ensure they get in for lunch if they're unable to get a dinner ADR or would prefer to see it and pay lunch prices. I know the place is supposed to be huge, but I wouldn't underestimate how many people want to get in here.
I know lots of Disney experts and fans would say that the avg person really isn't in tune with FLE and the hype over BoG, but I've had enough people - people who have never been or only been once - approach me over the last few months wondering if I knew anything about BoG and FLE completion dates. i.e. a larger population is anticipating this opening than normal.
Some have suggested that the anticipated volumes coupled with the more formal plating could be a sign that we could see our very first CS meal that requires ADRs...or at the very least, some kind of fastpass system. This is all rumor and speculation, but I have a feeling we'll be finding out more very soon.