Never ridden the Banana magic, but I hear its very responsive and has solid edge hold. I agree you may want to sharpen the edges.
Still even if they are fairly dull (unless they are totally f***ed) if you bend your knees enough and get your center of gravity nice and low you should be able to turn sharply with control.
It may also be that you just need to make some minor adjustments to the way you weight the boards edge in the turn compared to the other boards you are familiar with.
This is off topic, but there are 2 people with the K2 turbo dream here and I am looking at it as a possible board to buy in the sales in Feb (Actually its for a friend who is planning on a new board).
any chance of a mini review?
Particularly interested in how it carves and floats in pow. I also hear it has very good pop.