I'll begin by taking the liberty to define Alpha binos in a matter-of-fact physics sense: stay away from roof prisms.
Next item, magnesium body is to keep weight low - these are already low weight so no need to use exotic materials.
As for lenses and coatings the Papilio II are already at or exceed roof prism alpha binos in transmission values when color, resolution and contrast are simultaneously evaluated (not to forget internal reflections, ghosting, etc).
Mechanics? I am hard pressed to imagine a more precise focusing mechanism and I've used lots of measuring instruments in standards-calibrated scientific and industrial labs. In fact, taking into account the distance the objective lenses travel to go from a close focus of 50cm to 'infinity' (read focus on a star) all the while maintaining a constant displacement of the right and left optical centers of their individual focal planes combined with simultaneous and precise rotations around this center to give stereo 2-eyed vision at unthought of close distances - well, whatever advances material scientists have made to make this possible is beyond my circle of knowledge, but not beyond my ability to appreciate a job superbly done (these are by necessity internal focus mechanisms so there are no exposed mechanical arms or levers to get misaligned).
This leaves an AFOV of 60, to take your acceptable low limit. The Papilio II 6.5x21 are at a 7.5º FOV while you're asking for 8º.
Half a degree off, so maybe not an instant buy, but surely a pondered knowledge-based informed buying purchase it be 😊!!!.