It looks to me like they got the gun placement a little off, the shoulder gun should be mounted to the front of the waist for a proper D weapon
Nasty looking piece to add to the Tau's ever growing arsenal. That massive gun seems awfully short range at least (looks like the D only has a 10" range...which I guess is well above average I can't stop..
) but that double-tap rule when you forgo your movement is pretty ripe. Don't want to move with your Tau super-model? Get to shoot twice! I guess this is what GW intends when they try to balance their models (was that too much?