In regard to O-Sensei's use of Morote dori - I would have to say that Saito Sensei would not put as much emphasis on this holding technique as he did unless O-Sensei also taught it extensively.
My feelings are the same as yours. I believe Saito Sensei tried with great effort to show Aikido the way he learned it from Ueshiba in Iwama. From what has been recorded of Ueshiba's work before the Iwama years would suggest that earlier in his career, he didn't do much (if any) two to one hand holding attacks. I wonder why this is?
To me, being from the Iwama lineage, I think of Morote Dori as a very prominent attack. I was shocked to see that Ueshiba didn't emphasize it in his early work. Makes me curious.