comparing the load characteristics of a wheel bearing to a pinion bearing??? COME ON MAN! Set your pinion bearing up "loose" like you mentioned that wheel bearing and let me know how that works. I realize the "loose bearing" crowd isn't talking "wheel bearing loose"... but throw some sort of disclaimer on that comparison.
Think about what is being torqued down. The torque load on the pinion nut is holding an interference load between the two inside races and either a spacer and shim pack or a crush collar. As much as 150-250 lb. ft. But the turning torque is only 15-25 in. lbs. The inner race is what is locked down, against the pinion gear face and yoke.
All I'm getting at is that the interference fit of the pinion shaft and inner bearing race surface isn't "that" critical, and can be modified for easier setup without compromising strength.
