Various trunk punch scores (well you can't punch the head, so I guess that's redundant). What I don't get is not using leg blocks (so my son says, he read the rules) - and yet much of the fight is spent with legs entangled. Frustrating mess to watch as someone who knows TKD, so goodness knows what it looks like to a non-martial artist. Seems Karate has been similarly watered down, which is bad news given the host nation!
My thoughts on this, hope it helps provide some insight in to where we are now and why we got here.
I think it helps if you come at it from a point of both understanding the Korean cultural background AND the business side of finding a niche and filling it (and let's not mistake this - Kukkiwon cares far less about money, they charge relatively low fees for things - WT however is a global business/sport with all that comes with it).
First part - Koreans have never liked face punching. From the early days of Taekkyeon they never wanted it in their sport. The reason given is that they were pottery makers and craftsmen as a nation and didn't want to risk breaking a hand. Whether that's the true reason or they just felt it uncouth, we may never know - but we know it's there.
Second part - imagine you're responsible for the multi-million point business that is defining a sport of Taekwondo. You have lots of impressive kicks and you want to differentiate yourself from Karate (so you can try to get in to the Olympics separately rather than as a flavour of Karate), what would you do in your rules? I'd say they'd go much as they have...
Punching to the head is already off limits as above, but we don't just want boxing to the body and people doing that all fight, we want them kicking. So let's de-emphasise them by making the point for a punch lower and them score far less often. We want to encourage lots of high kicking action so let's give more points for the head and more points for spinning.
Now, when that Steven Lopez chap was around, he actually blocked with his lower leg quite often and it made for very boring fights because it turns out no one wanted to attack and end up doing a painful shin/foot on shin or shin/foot on knee kick. So we'll change the rules to penalise anyone doing that.
Lots of hugging, that's not exciting kicking action - so let's allow pushing to try to allow players to break that stalemate of the clinch. But we don't want them just pushing each other to the floor if the other is trying to kick (we want to encourage kicking) so we'll penalise if they do that.
That's pretty much how the evolution of the rules has gone - with every step being with a mindset of "we have exciting kicks which is different to most other martial arts, how can we show them off, and try to reduce things that stop people showing them off".
The common question I hear is "why don't we allow X in Taekwondo like we do in Y, then it would be better" where X is leg blocking, leg kicks, face punching, takedowns, whatever. The reason is that when you do - you change the game. You don't just add something in, suddenly the strategies that most competitors will use will be whatever wins them matches - so you risk "why bother kicking if I can just slip the first kick, take them down and get the points".
You also lose the uniqueness of WT Taekwondo and it becomes "just like Thai Boxing" or "just like MMA" and what's the point in that, those sports already exist! If you want leg blocks, leg kicks, face punches - do Thai boxing.
