You probably won't know if all you know is shoulder driven movement in terms of feel.
There are some things you can watch for. For example for suburi watch the following:
The motion begins in the middle of the body and propagates outwards into the arms and legs. This forces the arms back (and the weightshift back). This is followed by a closing motion as the weight shifts forwards. You might notice some motion in the front leg as the body becomes convex to offset the "crunch" in the middle.
Well I don't like it, and you can bet the house on the fact that there are "others" in certain koryu arts who wouldn't look twice at it either. There are better ways to move and frankly his body movements are a dead give away of what NOT to do if you were looking for mobility and consistent power. This ties in to what I was talking about with spear shaking. Some guys opt for this certain store and release model that can issue good power, and it echoes what they do in their crossing hands, but like this guy here, you can see it a mile off, it is limited and it has a start and finish that is both limiting and obvious. There are better ways to move where the power is continuously accessible and very free. That way of moving would never cut it in certain circles, but because it does have some power it can fool a lot of people into thinking "This must be... the... way."
I would never move like that and yet I cut through 3" trees. Some can try to convince you and others here it is muscle. People can believe whatever internet nonsense they like. yet I have taught women and smaller men to do the same thing. Weapons can be very defining when it comes to muscle use.
Most people with real weapons experience know this already.
Leaving you aside for a moment I would address this whole "essence of everything"
theory that keeps coming up. It isn't said, it is just implied. Internal movement is not all the same, internal skills in use
even more so (although there are certain key components in IP that are universal).
This video and others with Ueshiba sword cutting have been talked to death here. They are yet another example of people in certain circles talking past their own skill level and thinking they get it. Lumping the body mechanics of Ueshiba and Tohei together (Tohei and Ueshiba did NOT move the same way) and then arm chair quarterbacking the body use in Japanese weapons and lumping them
together as well.
I have seen certain so called internal coaches
advertising their movement is directly related to the use of Japanese weapons, when it is glaringly obvious, and well discussed in certain... cough... "informed circles" that you just cannot move that way with weapons. Of course you would have to know the difference to understand why. Some of these things are pretty direct and easily shown, better still demonstrated by taking apart senior exponents in those arts. Talk is cheap.
People carefully qualify that not all internal training is the same....but when you see them on all these boards discussing ; Judo, jujutsu, Karate, Taichi, Bagua, Xing I, AIkido, Daito ryu and Koryu weapons with their "essence of everything" theories without ever managing to actually show competent skills in those arts or clearly demonstrate...to those who ARE competent in those arts, how their own arts operate with and without IP/aiki components and where they make a difference and instead default back to talking...about the "essence of everything"
theory, it leaves me and others to wonder. Again ...talk is cheap. Oh well.
Power is a good thing, but it is the first baby step on your way to true competence, it can be overcome. I guess when people are unfamiliar with that type of power it can be impressive. However, expressing IP/aiki in a full range of movement in martial disciplines involves a more sophisticated and complex understanding than that.
I guess I will just have to agree with them.
"IP/aiki training is not all the same."
As they say....buyer beware. It pays to go to a lot of places and get what you need as you grow in the arts.