That argument isn't one-sided. Excadrill instantly becomes it's worst enemy if it gives up Sand Rush, as opposing Excadrill on Sandstorm teams will wreck it... 'course, in a more casual environment, Sandstorm abuse in Singles or Doubles ain't anywhere as prevalent, so I s'pose Mold Breaker would be worth it. Makes ChargeQuake abuse that much more effective.
... Though Gliscor is still your worst enemy. Not that anyone of sound mind would often use one in Doubles.