True... but I wonder how much of their styles are reflected in their student? For example, Yasuno Sensei/Nakao Sensei/Tissier Sensei were all deshi of Yamaguchi Sensei. I know some people who have trained under both Yamaguchi Sensei and Yasuno Sensei... just wondering how much of Yamaguchi Sensei's style is reflected in their styles...
Just like Kubota Sensei/Irie Sensei are students of Tada Sensei... Up till now, I believe that Aikido is a personal thing and each person's Aikido is a reflection of their personality... but how much of Tada Sensei can be seen in Kubota Sensei/Irie Sensei?
Just some thoughts
In general, very little.
However, I am not sure what point you are making here. For reasons of their own, the three shihans I mentioned never wrote anything or made tapes, so the only way you could ever experience their aikido is going to classes and seminars. Thus, your observations about their so-called students would fit, except that the shihans themselves did not consider it their business to produce 'replicas' of their aikido in those who trained under their direction. Accordingly, any similarities are fortuitous.
Why is this? Well, my own opinion is that these three shihans tried as much as possible to reproduce Morihei Ueshiba's own teaching methodology, such as it was.