Not a bad list, seems very well rounded. I have two concerns, the first being Margara. In our games she typically only gets one firestorm off to mediocre effect, then is squished like a bug (if she isn't squished before she gets a spell off). I like her stats, but in actual play she has never been able to influence much in the game.
The second concern is almost all the soldiers have a DV under 10. The one that has a dv that high also has provoke, which won't help him live long. A high number of damage tracks is nice, but you don't seem to have the horde numbers to make up for the low dvs. Now having said that your list could be very durable in actual game play, so please let us know how it does if you play it. We have had several bondslaves and other low dv units live much longer than they should.
But yeah, the Stone Spirit is really nice. I don't think I've ever seen him under perform.