You stay in villas because you want more space or you want to cook. You're not cooking, so I'll discuss the space issue. The one-bedroom villas are great for families. Having two real rooms with a door between allows kids to nap while adults can move around. Similarly, at night, adults can stay up and watch a movie or get romantic room service without bothering the children. However, there is also something to be said for cozy one-room accommodations when you want to bond with your family or when, for budgetary or other reasons, more space is not an option. You can see my response to a question about one-room living
here.
If you decide that you don't mind staying in one room, then I have a question. Why choose to stay in a villa studio as opposed to a standard hotel room? A studio room is just like a regular hotel room but with the addition of a small kitchenette (refrigerator and microwave). This is a nice option for Disney Vacation Club members who are staying at the villas on their points. But the studio villas don't make any sense at all financially when paying with money unless you really need the microwave (regular rooms still have a mini-refrigerator).
These prices could change, so just use them as a reference... In 2008, during the value season, a standard room at the Wilderness Lodge is $225 per night. A studio at the WL Villas is $315 per night. You could even get one of the nicer rooms at the WL (courtyard bunk bed) for $305, which is still less than the studio and probably more fun for the kids.
That was all a long way of saying that the one-bedroom villas are fabulous for families. But if you have a good attitude and a sense of humor, staying in one room can also work. If you decide to stay in one room, unless you plan to microwave a lot, then a regular room is much more cost effective than a villa studio room.