IMO, if you have weak ankles then you should go with a stiffer boot that wont give as easily putting more pressure on your ankles. If you are able to twist your ankles then you're gonna get hurt.
I just bought a pair of the DC Judge boots, it has dual zone Boa system. It holds the ankles in pretty tight and keeps it pretty stiff. Real nice. But then I just tried on the Burton Imperial 2012 and it fit my foot like a glove right out of the box. Nice lean and slender profile. It has "cushioning" like in the Nice Air max shoe.
Sports chalet is setting up for the Labor Day weekend sale. Those boots will most likely be 50-70% off. That drops both boots to around $100 each.