Movement is not immutable. The same open-handed sweep to the side with my left arm could be a block or a grab or a parry or a strike or a part of something else such a throw or a combination technique. The only difference is the actual part of the arm I make contact with, what part of my opponent I am touching, and the speed and desired effect I am imparting. Yet to the casual observer, any one of those things looks the same practiced in the air without a visible partner or target to work with. Adjunct to that, most people probably see a 'block' with in a pattern as a block, and this has been compounded by decades of teachers teaching the same phenomenon, likely stemming from the whole Itosu/Funakoshi youth/karate popularization effort.
I can't disagree with that. It would appear that many things that are actually techniques that I would use in Hapkido, or you would use in Aikido, specific to a particular attack, have been modified to an extent, to fit the TKD thought process of block, then attack. Probably when first included in the forms, the teachers knew, and told their students, what was going on. A lot of that seems to have been lost from the teaching process.
As to your comment that a block could be a grab or a parry or a strike, I would answer that first it must be a block. You first have to block/parry it so it doesn't hit you. Then, and as a continuation of the move, you most certainly may grab or strike some other part of the attacker's person.
As for why blocking is inefficient... Some thoughts below.
First, you do hapkido correct? Is the path of least resistance to block or is it only a last resort? Certainly in the aikido I study we don't generally want to solidify ourselves and push back at force with our own force, even if we can do so more intelligently by taking a different angle to avoid the brunt of the attacker's strength. Instead we seek to blend with our attacker (or is it to gather him into our hara?) and in so doing we neutralize him.
Well, first of all, I can't think of a block I learned in Hapkido, or TKD, that was a direct confrontation to the punch or kick, meeting it with force of my own to stop it. It was always movement to the side. I remember being corrected by Mr. Rhee when I tried to do otherwise, and him telling that the particular kick was too powerful for that as a defense. The only exception I can think of in Hapkido, is sword defense. Sometimes engaging the sword with a short stick, and then bringing it down to stop just above the head as energy is absorbed, is the only possible defense. Not something I would like to do, but if it was all I had, it is a tool. That isn't taught until after attainment of 1st Dan. That assumes some speed, strength, and timing already learned.
Second, blocking represents an opportunity cost of sorts. When you commit yourself to making a block, you are undeniably choosing to do this over another alternative. What if you could move in such a fashion as to avoid the attack while simultaneously counterattacking yourself? Is that not better tactically?
Certainly a point for consideration. As I was taught, we would block as we move in, a counter-attack being part of the entire movement. We have very few counters to a punch or kick where we would not first block, or block as part of the counter. But blocking when it is used, is normally much as you describe; avoiding the attack and counter-attacking.
For example, if someone throws a side kick at you, what do you do? 1) Do you try to block a side kick with a down block or a side block standing roughly where you are already? Hmm, good luck with that. 2) Do you step back or to an angle to avoid the kick before countering with your own kick as is taught in a sport sparring match? Better I suppose, but I think acquiring closer range is imperative to ending a true fight. You don't want to drag things out and exchange shots at each other. 3) Do we step to the side to avoid the kick while covering up with a block before truncating with a series of counterstrikes as is frequently taught in many one and three step sparring sets? Also better than option 1, but there's still that opportunity cost taken up. 4) Do we move in such a fashion that we avoid the attack and in same movement counter effective. IMO this is best. An example would be angling one's torso to let the kick slip by while immediately attacking the kicker's jawline with a ridgehand that converts into reverse hip toss once we have entered in behind the strike.
We have many defenses. Mostly we block first as we move in to counter. Before attaining 1st Dan, in the Hapkido I learned, I was taught 9 blocks, some high, some low, some middle. Then I was taught 5 blocks and strikes, 5 blocks and breaks, and then 5 blocks and throws.
To your questions, number 1, with a side block. is certainly one of the ways I learned in TKD. As to Number 2, you might want to add this to your tool kit: Step back long (enough), covering your rib cage with your left hand (assuming the left foot forward), bring your right hand in an arc up and down with a back knuckle strike to your opponent's ankle bone, just as he has full extention. The rest of the worries you had are gone. Break or not, that foot is no longer working well for your opponent. If he is the only one, take him out as you wish or leave. If more than one, the first isn't going to attack you before you can defend other(s). Number 3 - for a right side kick, move forward to the left, away from the kick. Sudo strike the calf with your right hand as you simultaneously ridge hand strike the shin with you left hand. Turn your right hand to the leg and slide both of them down, whether you opponent is trying to withdraw the leg or not. Your left hand will catch the forward part of the foot, the right the heel. Twist the heel up and the toes down, and if you wish, lower the leg to rotate the leg even more. Walk away covering your ears to lessen the sound of the screams of the dislocated knee/hip. ;-) This will also work for number 4. Your solution is also quite doable, if a little more complicated, and depending on you attacker still being there for you to step behind. With your kind permission, I will add that to my tool kit. We had some counters where we stepped to the side of a kick, and raised the same arm as the kicking leg up, and trapped it with our arm, then counter attacked in one of several ways, such as stepping forward and kicking down on the calf of the opponent's plant leg, forcing him to fall backwards with an injured calf, or with our other hand, grabbing his leg at about the knee and pulling it forcefully to dislocate it.
As I mentioned, we have more defenses than I mentioned, plus more blocks and counters are learned before attaining 2nd Dan.
Now do we always have four options like I presented here. Well, no. But, the more you train the more options you have and I'd rather train for alternatives like #4.
Third, say we just like blocking. It makes sense to us, we think we can do it successfully, so why not block, yada, yada. Well, the main reason is that most people don't condition their arms like they should if they really want blocking to work for them. I mean in the destroy your attacker's arm sense. That's real blocking. The old Hung Gar people go crazy with all the arm banging they do to build up bone density. So do the hardcore Goju-ryu karate people with their kotikitae. Respectfully, just as the spear hand strike is an 'archaic' remnant from the days when martial artists conditioned their fingers, so too is blocking an artifact of times past when arm conditioning was a lot more prevalent. Don't get me wrong, I am not saying that blocking can't work if we don't condition our arms. It can, but I would suspect that instead of blocking and destroying the attacker's capacity to hurt us, we now really mean blocking and absorbing force, which is less than optimal IMO.
That is a very good point. But that mostly if you are trying to break something with your block (not a bad idea in itself). Most blocks only need to move the mass of the limb enought to the side to avoid being hit by fist, foot or knee. Much less force needed. But combine the block with the speed that is normally necessary, and yes, you need some toughening