We just got back from a stay in a dedicated 2BR. The balcony is large, and can be accessed from the living room and the master BR.
My children are teenagers so there aren't many pros or cons for us to get a dedicated vs lock off. We've had both and enjoyed both.
With the lock off, the second bedroom has a kitchenette and separate entrance and climate controls.
With the dedicated 2BR, the second bedroom has no kitchenette or outside entry, both of which are converted into more floor and/or closet space depending on the resort.
Some people with smaller children don't like the second bedroom in a lock off having a separate entrance that mischievous children might open and wander out.
For us, either one works fine.