Maybe I am misreading your statement here, but in many of your posts on aiki, you have stated that Shioda had aiki. Now, you are saying he had aiki to a degree. How can you say what he had/didn't have when you haven't touched hands with the man? Not trying to be a wise ass, just looking for consistancy. This question is not meant to be hostile, just trying to learn about this stuff by research, examples and of course my own practice with others.
There is no hostility needed-we can agee or disagree on a body of work without emotion. I'm not goingg to get upset if you disagree with me over a hobby.
I look at all of this like a better way to work. If someone shows up on a job site with a better tool and method to cut wood-the carpenters there would not have an ego or vested interest in their previous method holding them back from working more efficiently and making a better living! I have seen it happen where entire crews change on the spot and/or buy knew equipment.
Budo should be the same way. Movement is movement. There are things you can see in interaction and movement. Shioda had many positive attributes in movement. He was clearly not troubled by many of the issues that plague many in the aiki arts when he was stressed with weight or pulled. All-in-all I think his skills were obvious and set hm apart from others of Ueshiba's students. That he chose the one-line model (many Japanese did) when it was clear he didn't have to was a choice he made. It can be powerful even for those moving externally -as long as they maintain that line- or they can get caught and be off-lined rather easily. For that reason timing and footwork has to take over to avoid the structural openings or weaknesses that type of movement can cause.
Shioda is an interesting study in that he trained in Aikido and Daito ryu. He clearly has aiki and he combines movement prevalent in some schools of Daito ryu yet retains movement seen in Aikido. Interestingly enough Hisa (who trained in both arts) did not retain much of the Aikido model but opted for more of the Daito ryu model. When you look at schools of Daito ryu you will see the same thing with some schools still retaining that one-line model and others moving from center and generating power quite differently.
Koryu is the same way. There are certain arts that move with large weapons and have handled that demand (certain schools more than others) by adopting certain modalities because it was quite simply a more efficient way to get the job done. Not by coincidence those patterns of movements are not typically seen in many of the modern arts-in particular the unarmed ones. Take the weapons out of the hands of certain arts adepts and you will find some very powerful, centered movement. Add some other training into the mix and you would see even more powerful movement...now supported on all sides.
IME, it is mistake to think that all "movement" and all methods are equal and some guys are just more powerful than others. There are more efficient ways to move; externally and internally and fighting with it or not, is a different topic all together.