Well, this is my 2 cents.........
Since you are staying in a studio and have 2 small children (1 young enough for a portacrib) you really do not need 2 beds. The baby can sleep in the portacrib and the 4 yo either in bed with you or on the sofa. Since you do not need 2 beds, I think a BCV studio would be better for you. Although technically the BCV studio is slightly smaller than an OKW studio, because the BCV studio has only 1 bed and more open floor space the studio feels much larger. You will also have more open space for the kids to play and to put the portacrib.
If you do not like to drive, the close parking at OKW will not be of any use to you. From OKW you will have to take a bus everywhere except DTD which has a boat. From BCV you can walk or boat to Epcot and MGM, bus to everywhere else. With little ones in a stroller it is much easier to walk or take a boat than getting on and off buses.
BCV's main pool SAB is absolutely amazing. Although it has some very deep spots it also has a very nice beach sand area and zero depth entry area that is perfect for your age kids. If you kids were older I would worry about them wandering off to a deep part of the pool, but at 1 & 4 they will be very content at the sand/beach area. OKW also has a nice main pool but it is not zero depth entry. BTW, kiddie meals at Hurricane Hannahs at SAB, come in a sand bucket with a shovel, so the kids will even have sand toys to play with!
You said you like VWL because there is so much to do right at the resort. BCV also has a lot to do right at the resort. You will have the boardwalk entertainment at night, you will be steps away from Epcot, restaurants and shops. BCV has the food court/store that is really nice for little ones.
Overall, I would recommend you keep your reservation as it is, and stay 7 nights at VWL and 7 nights at BCV. It is very tempting to have 2 extra nights, but 14 nights is a long trip and you may be very ready to come home after 2 weeks away. Also considering your traveling group and your preferences, I think BCV is better suited for you. Both resorts are very nice but BCV is a better fit, at this time, imo.
Have a great trip!