How about making Ghost of the Dunes a power-up to Dervishes as a whole? As in, it's a part of the Dervish Dance now inherently? In the same vein, maybe make it three hits regardless of vision?

Justification: Currently, the desert terrain seems very lacking (and yes, I'm biased). If it were me, I'd make Sandswirl work anywhere reliably, much like Vanish with Smoke and Mirrors now does. Not adding to killing ability, but making a completely unused skill suddenly a fix to the terrain, plus it makes sense IC. Why couldn't a bedouin throw some sand in the air while he makes the escape? But you'd never go for it, so I merely propose a three-hit dervishdance. Not OP by any means, but a requirement on all bedouins nonetheless. I challenge you to find anyone who wouldn't want to take it, thus making it perfect for a basic class ability.