Preferred option would be to allow a person to watch the video live, concurrently with their movements - in a repetitive sport like mine, this is possible - in Aikido it's a little more difficult to provide concurrent video feedback because you're constantly changing your viewpoint, and (should be) focusing on uke or nage, and not a mirror or a video monitor.
I pretty much agree with what you have said.
Yeah, you have to focus on uke/nage.
That is why the supplement video was good for me.
Not saying that mirrors cant help, etc.
But with Aikido, it seems that its more complex and the best way is to approach learning from different angles. (At least for me that is what has worked thus far.)