I think you misunderstood a topic. This topic is not "how to improve your taijutsu with aikiken practice'. The author asked how to improve cutting with a sword. Please reread his first post.
Sorry to confuse you, my comments about taijutsu were referring to the content of the helpful link I provided, not to the OP.
In fact the OP says "When I swing my sword ... I just can't seem to get the tip of the sword to go straight." This is the point-- he is trying to make his body move an object in a straight line, but it doesn't happen. This is an important point about perfecting the self, controlling your body, being able to move in a special (useful) way. If it isn't clear to you, that's a different topic than the fact that this is indeed an important point to Steve and the rest of us.
It's not about swordsmanship, it's about failure to be able to make your body do a simple task the way one wants it done.