I honestly don't think you even need CC vs. EX (IIRC, this was how it worked in first beta). The fact that they lost meter AND are eating a full (non-CC) punish is enough, especially since EX DPs have fierce DP recovery. However, I would ensure that EX DPs do not crossup on block.
That part, at least, is being addressed in the April patch: all medium DPs will have full invincibility to airborne attacks.now what have as result is no one using them for even anti airs.