Getting into the logistics for a second, everything animal related pretty much has to be around the perimeter for the animal care facilities.
I guess the interstitial sections of the park is where the future attractions need to to alleviate what seems like long stretches. They do this already by spreading out the shops and eateries.
An interesting point about the walking though; would we have those same complaints if DAK opened 30 years ago?
Logistically, yes, the dark rides would have to be placed interstitially, although some areas are probably large enough for monkeys and other animals that don't require a savannah.
I remember hearing people complain about walking at the Magic Kingdom, and I suspect DAK would have been just as daunting back then.