Striking arts operate at a much faster pace so you really can't do that, the depth of the decision trees are much shorter, which is why I think bjj is more analytical and appropriate for most HNers.
I don't want to get into a flame war, but I personally don't find taekwondo and karate to be particularly realistic to fighting. Everyone has different motivations for training though, if you enjoy the fitness and athleticism of those arts, go for it.
I have fairly high level belts in several arts. My father put my in Judo when I was 4, jiu-jitsu and Taekwondo by 6. While there are some Karate styles that have become obsolete with more contemporary arts surpassing them (Kempo comes to mind). I believe that Taekwondo is still a very relevant art even for combat.
Taekwondo while extremely difficult due to the technical kicking requirements is by far the most superior kicking art. The problem is that it is not a rounded art. In combat you cannot rely on the fact that you will land the kick ever time and Taekwondo does not really focus on that fact, it has to be augmented with another art. Which usually in Taekwondo schools is Hapkido. The problem is Hapkido is inferior to Aikido or jiu-jitsu.
That being said, my son is now 4 and the first art I enrolled him in was Taekwondo. Doing so will allow him to develop superior kicking technique which take the body the longest time to develop and some people after aging are never able to achieve the limberness required to master Taekwondo.
I agree with you to the extent that Taekwondo on it's own does not round a person enough to be confident in a street fight. But as an augmentation to other arts it will give you superior leg work over any other art and is very relevant to modern street combat. In the few altercations, that I could not avoid getting into, 2 where ended by a single kick and both where head kicks that are only taught in Taekwondo, so it is effective you just cannot rely on it as your only weapon.
I think the opportunity to practice something with the analytical element discussed here is great. Really, all martial arts are highly analytical, but different martial arts afford different opportunities to use these skills. I think all martial arts (or martial art sports) involving competition have similar levels of analysis, but lots of martial arts instructors require you to reach some sort of physical foundation before teaching you any true technical aspects. So, as said, it all depends on what you want.