Well, yes and no. A restaurant that is full is no problem, but if the restaurant is constantly completely overbooked, taking reservations for months out, and still making patrons wait an hour for a table after arrival, well, they might want to look into expanding their operation.
I do think Disney is at a point where some expansion is warranted, or at least using all of the currently available spaces that the parks have. Like there is no reason why places like the Tomorrowland north building or Wonders of Life are completely unused. Start there at the very least - it is compeltely warranted with current business levels.