Yes, except: (Unless my sword training is v.questionible) would one do that in a v.casual stance, hold the sword in a way (straight / horizontal) that is very difficult to
stop a stong blow, not move off line, etc ?
In my opinion, "casual" is not a proper attitude to have when studying Aikido with swords, ever. You get the most out of training with swords when you approach it with an attitude of "shit has just gotten really real."
I think he should be projecting the intention to cut you down at that point in the kata and you should be trying to read his intention to cut you down.
On a technical note, if the posture in question here is actually an implied nagashi, then it is not necessarily bad if it look like it could not "stop a strong blow." It's a combined offensive / defensive movement that is blending or deflecting in nature.
Some, in this exercise, seem to want to cut straight back from this positon, expecting the other to move back and recieve the cut down their sword, with the hands out of range from the cut. Except they started that cut with my sword 1 inch from their head ... all I have to do is move off line to the outside and cut down their face, turn to my right - their outside - meet their cut and exit.
I am starting to wonder if I have been shown a corrupted or at least misunderstood exercise. The only point I can see is if the original statement holds true, beginers wacking practice and DONT hit my head.
The problem is more that you and possibly your training partners are spinning your gears trying to feel a martial narrative that is not there. Kumitachi are meant to instill principals. Sometimes they instill principals by making you worry about something basic like not getting hit or completing a complex move with a certain timing. Other times, its something that looks nothing at all like combat.
The solution for you is to find yourself a well-qualified instructor, have him or her show you the kata, and simply do your best to do exactly
what you are taught, nothing more or less. If you must analyze, do so with a very open mind.