the yokomen strike that we practiced isn't the standard wideass swing that many aikido folks do. it's more like the karate reverse knife hand strike. the trajectory is straight in like a punch to the face with a hips rotation at the end to give it a slight curve. ya, our yokomen took the center line, then slight deviation at the end to go for the side of the throat. normal aikido entry as you described above won't work. just my 2 cents.
Hmmm. Yeah I dunno. Yokomenuchi and shomenuchi are really supposed to be sword cuts. But it is understandable to feel like you are wasting uke's training time by having her spend all of this energy making a pretend sword cut, so the tendency is going to be to change them both into hammerfists or something, with a flatter trajectory and less windup.
Theoretically, somebody could pull off the entry I am describing on a flat-trajectory strike that has minimal wind up, but in practice it will always be sort of a mess and you'd naturally find some other technique to do instead.
I'd still like to give a try....