Without knowing any of the models fluff, its hard to really judge the design beyond comparing to previous models and previously defined fluff.
Exposed Pilots and dual heads doesn't make a whole lot of sense. An argument could be made that the two heads are for the weapons to be targetted independantly, and so two pilots are need, but that still leaves the gapping question of the open-topped cockpit....
Arms aren't exactly beyond design, as seen with the Bird of Prey Typhoon:
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However that would have made the shoulders and back increadibly cluster, and so perhaps and underarm design would have been better.
The stabilizers don't look good either, for the reasons you've said. for such a top heavy mech, the most logical choice, in my mind, would have been a tripod platform. Though this may not work so well with Tau aesthetic, it would have made more sense as a tripod is leagues more stable than a biped.
Considering the amount of plastic, I can't help but feel there is a lot of blank slabs of "Metal" that are likely meant for the hobbyist to fill with whatever their imagination dictates, or for Sept specific iconography.
As a it, it would be very expensive conversion fodder, and I'd likely not build it for the intended purpose. I'd likely cannabalize the weapons onto a Riptide, as they do look impressive. Here they're just poorly placed and feel slapped together onto a hulking mess of a mech body.
