One thing you can try if you have the people with you is have part of your party stand in line while the rest of you go on a ride or shop then switch places so you are not all standing in line the whole time. ToT and RRC are both close by as are most of the parks shops.
Steve
I just wanted to chime in on this comment because it's something you *SHOULDN'T* do with Fantasmic at WDW, at least not on a moderate or busy night where the theater might reach capacity.
At the Studios, Fantasmic is shown in an outdoor controlled-access amphitheater. As you enter, you pass through photocell turnstiles. When the counter reaches 8900 (or whatever the exact capacity is), they CLOSE the entrance and they don't let ANYONE else in. If your family enters the theater and then some people leave, their departure is read by the turnstiles, and their "spots" are added back into the available total. So if the theater were to fill up while they were gone, the gates would be closed and they wouldn't be let back in, even with the "but my family is in there" line. Capacity is capacity.
So unless it's a slow enough day that the theater won't reach capacity, you don't want to split your group up. (And as you said you've only seen Disneyland's, I can see why you thought the suggestion would be OK. At Disneyland you can claim your space and have some people hold down the fort while other go off into the park. There's no controlled access.)
But you don't have to worry about losing their spots for getting up for things like restrooms and food. There are restrooms and food stands (with limited selections) within the amphitheater after the point where you go through the turnstiles.
-Rob
EDIT: Sorry, I just re-read the post I quoted, and it was referring to people switching out while standing in line rather than in the theater. Though the suggested tactic WOULD be possible, it also consitutes line cutting under most parks' rules (though not sure what Disney's policy is).
Also, the only "bad" seats I've ever had were ones that are directly under one of the support arms of the overhead truss. Not the tall horizontal ones at the front that follow the curve of the water, but rather the two that come off that front one and slope down toward the back of the theater. Being directly in line with this puts one of the support poles directly in line with the center of the stage, blocking some view of a couple scenes (the Evil Queen/Hag scene is one that comes to mind, also some of Pocahontas). It doesn't block a lot, but rather it's just annoying to have this pole in your line of sight.
