Um, forgive me if I've missed the point, but I don't think you've answered my question
You may be in a confined space so a low kick with a shin maybe all thats on offer.
OK, that's where you might want to use a shin. That means in that case, a shin is an option it have. No problem with that, it's another tool to use. At that range, though, knees and hands are also options. All that really says is that a shin is a tool to have available, it does not really say why using ball of feet, insteps or heels is not also a good tool.
A kick with a shin maybe less powerful, but then you don't want kill them. Like the unlucky Australian.
That kinda makes no sense. First off, your initial post on the subject said 'for real power...', which this says the opposite, but more importantly, in *any* attack you need to judge appropriate power. I spar lightly, or heavy; it's my self-control that makes the difference. Here your are saying 'use a less powerful too, it's safer' and I think I'd rather have a more powerful tool and scale it's usage as needed. In some situations, I may *need* that power, in others, I may not...regardless of what technique or striking surface I use
3. Closing the distance is no bad thing, it limits what your attack/opponent can do
The closer I am to an opponent, the closer he is to me. Logically, if closing distance limits his options, it also limits mine. Frankly, I'd rather have the option to attack him at range if I can. If he closes, tactics change, but...choice is nice.
There is more chance of kick landing to the body than a kick to the head, whatever the power. So why take a chance and fire at the head?i
That was my point. Tactically, it's probably a bad idea to do it. However, if you do it, it's going to have the same power whether it's against a sparring opponent with pads or a drunk idiot. The power of any attack is going to be the same, regardless of the target (the spinning kick to the head was an example of a move that's not tactically wise in a real street fight, but the point is that the power that can break a board can break a leg)
Maybe you should consider practising shorter range kicks on the heavy-bag
Or practice short and long. Choice of range and choice of power is..again...a nice option to have available.
Also, if I work on short kicks with shins, that still makes my long kicks more powerful. A roundhouse is a roundhouse. If I improve my roundhouse so that kicking with the shin is stronger, that will improve me leg strength, foot speed, and hip snap and make my roundhouse kick even more powerful when striking with the ball of the foot (or instep)
and just as a personal thought, the foot is designed to flex so hits to the instep can flex and aborb, the heel is designed to take force straight on, as is the ball of the foot. The shin is *not* designed to take force from the side as I'll admit it makes me nervous to use it as a striking surface
You are not betraying tkd by refining methods to suit you for the street.
I don't mind refining methods. We train for a lot of things that make no sense in sparring but are used for self-defense and street fighting, including knees and elbows for striking and breaking opponent knees and elbows and drawing some from Hapkido, etc...for joint manipulation and close range strikes
Adding techniques is fine, but this stuff was also developed by people very interested in combat fighting so before I reject a technique, a really want to understand why it's not useful for fighting and why I would reject it.
So far you've said "this technique is good" and I agree being able to add a non-standard technique borrowed from another discipline is a good idea, but you've also said "that technique is bad" and I've asked "why?" because the technique you are saying to reject is something that adds range (physiology) and power (physics) and more options and before I reject those tools I want to really know why and you've explained why to add some tools but not why to reject the others