Some recent stills of Kuch's (same star) new boots. The more I see them, the more they look like the outsole really has crept up onto the quarters, cupping the midfoot and heel.
My thought is, this is Bauer's initial response to the VH/True and CCM monocoque boots. They look like Bauer's interpretation of the Mako is finally here. Even some of the lines of the Mako are still there: of course there's the newer, sleeker toe cap that's already known from the Vapor lineup, but the wrap on Kuch's boots is reminiscent of the Makos (though with more negative space involved in this instance) as is the thick seam where the exposed composite met the plastic wrapping the Makos. In this case it looks like an inversion of its predecessor: instead of the shell of the boot going from exposed to covered as it did on the Mako, the shell of this stealthpreme still appears to be a "two-piece" boot construction with the composite quarters married to the outsole so that the prominent seam marks the end of the outsole's incursion up the rearward sides of the boot.
This makes sense. If it's a viable design, it could allow Bauer to reap similar perceived benefits of the monocoque construction ("perceived" because there are plenty of both yay and naysayers) while minimizing the degree to which they have to alter their construction methods. It can't really be a question of developing their own monocoque boot from scratch, since they own the IP for the Mako. This looks to be Bauer staying true to their ways, which still has them in a fairly comfortable lead in market share if I'm not mistaken, while attempting to fend off competition that has eaten somewhat into that market share of late.
My experience in a monocoque boot (MLX) has made me think the real performance trick has to do with its minimizing torsion which I can easily picture being exaggerated between the various parts that make up the traditional hockey boot twisting independently, as they are subjected to opposing forces in acceleration maneuvers and therefore pull away from each other somewhat. A monocoque boot would unify that system into one part that still probably twists, but as one thing rather than several, which makes for a more much more immediate response. I have no experimental or theoretical physical model showing that this is indeed what happens, it's just what it feels like going from other boots to MLX, and how I picture that feeling when I draw it in my head. There's probably a deal more redundant material in that heel/quarter/outsole sandwich than there would be on Bauer's skates with traditional outsoles which run roughly parallel to the ground (we're a long way removed from OD1N's "LET'S DELETE THE OUTSOLE!!!"), but if this can mimic that reduced interstitial torsion of a monocoque OPB it could be well worth it.