One use of Cassian crew I haven't seen discussed here yet: blocking x7 Defenders. Since you know those Defenders are going to be using their 4K like mad, this seems to be an obvious way to reduce that effectiveness. Pretty much no maneuver in the game is easier to predict than when an x7 is going to k-turn...
And blocking one can cause a chain reaction pileup, since they often do it together. If you can get them to rethink their strategy on when/how to use the 4K, it may significantly affect those lists.
Seriously. The times when Defenders can basically choose a K Turn or a 3 Turn in one direction only because of ship and rock placements, are so frequent that Cassian will thrive on them.