Run under RH is a faster scenario/pacing option, you can rush in immediately after contact with no delay unlike an uppercut.
It can't be favoritism when the hit boxes are generally based on the animation speed and position. We can't change the collision box of the character being hit, so that's a limit we have to deal with. This leaves us with only being able to compensate on the hot collisions, which if all adjusted to be better, starts to ruin some of the visual aspect of timing. If John Turk just has physically good mechanics and all his moves wound up being useful, that's inherent to the game's design in an indirect way. If you start messing with shit like, making Sheeva's RH as fast as most everyone else's, or better, everyone's as fast as Sonya's, it is a change that is perhaps, not necessary just to give her something that matches up with everyone else. Sheeva's aaRH is meant for long distance jumps generally, female ninjas as stated, good for run under. With the right timing though, RH's can be used for anti air with everyone, it depends when the other person attacks. There are plenty of RHs in the game that don't feel super great for anti air, but if every single RH had the same hot collision at the very least, the game would feel watered down in that respect. We could do the same for every normal. So, yes, in a sense if other characters have better anti airs from specials, they should use those, as that's part of their package, and if a character has a bunch of good normals, that's a strength to that character. Maybe they shouldn't be as powerful in other respects. I just don't want to see too much normalization. Damage I can understand for normals, and in some cases throws and projectiles, but that stuff has been tweaked here and there. MKII and MK1 are better examples because of the random, minuscule differences that almost seem like accidents, some RHs are 1 pixel more than others? Weird.