4wd vehicles have (I believe) three differentials. One between the front two wheels, one between the rear two wheels, and one between the front and rear axles.
The majority of 4wd trucks (jeeps, etc) have a 2wd and a 4wd gear you select between. In 4wd mode, usually ALL differentials are locked, and every wheel turns the exact same amount. This causes difficulty when turning (some wheels are inside the curve, others are outside, in fact every wheel travels a different distance, but they all turn the same number of rotations, leading to wheel hop and skidding). This is why these cars have a 2wd gear, so that you can drive on roads without this problem, yet you've got 4wd for offroading or slippery conditions. That's also why you need more throttle to turn, basically you are dragging some of your wheels along.
A "limited slip" differential (sometimes called "positraction" for cars) is one that allows a certain amount of difference in how much the wheels turn, so that you don't have wheel skidding around turns, but you still have power to your other wheel(s) if one wheel loses traction. This is what the Ravs have between their front two wheels, and between their rear two wheels. However, the center differential is available as either locking (manually, you push a button) or limited slip (more expensive option). I believe either was available for both automatic and manual transmissions. If your center differential is locking, and you don't have it locked, if you lose traction to BOTH front or BOTH rear wheels you might not go anywhere, just spin those wheels. This is not the case with the center limited slip diff. However, if you do have your center diff locked, you may experience some wheel skip and more throttle needed when making turns (although not as much as with a jeep, since the front and rear diff.s are still limited slip).
So, basically, the answer is NO, most Ravs will NOT experience the difficulty turning that some 4wd vehicles (mostly trucks) do.
As an interesting factoid, I believe all Subarus have limited slip differentials (often this is called All-wheel drive instead of 4-wheel drive).