Very interesting thread! I can't choose which views are more correct. Honestly I think that all of you tell something which is true, but that is not the whole truth.
First- there were times in which I've believed that the kickboxing/ muay thai are much more suitable for taller persons. I was sure that almost everything which one short person can do to a taller guy, would be even easier for the tall guy to do it to his shorter opponent. And let's look, it might be true- in many occasions- the shorter guys can't kick or knee the taller guys in the head. The elbows are probably also a little bit easier for the taller dudes (I am not sure here, I don't have much experience with elbows). And about the punching- again the taller guys have the edge, because they have longer reach usually and it it easier to punch down, not up. And realistically let's face it- the wins of the shorter guys usually come with the use of combos from close distance or with bombs. Thinking like this the boxing aspect is the only area in which the short guys are able to make something good (in most cases). So at first look it seems that the guys who say that MT is better for taller guys and worse for shorter are right, but....
After years I realized, partially from my old man, who also has some martial arts experience and is a huge fan of the combat sports at all that the boxing is not so bad for the taller persons. Yeah in KB/ MT you are allowed to kick and so what? When you stay on outside and try to kick you loose some of your footwork in the moment of kicking and your opponent can step outside or counter if he is quicker, which is quite possible. When you kick, he can block and enter in close range, where he can kick also or just throw some bombs with his arms. If you decide to use jabs and crosses, good- you'll have good mobility, but he would still be able to kick you and to chop you down, or make you to start checking or blocking the kicks and be more static which is going to give him the opportunity to get inside and start trading with you. The big weapon of the taller fighters- the knees, yeah they are great, but they are not so long ranged weapons. If you want to use them, you have to close the distance and he can swarm you with punches. Of course, you can use them as a counter of his inside boxing fighting, but this is another story.
So now I've changed my mind again and I don't think that the boxing or the KB/ MT are superior for tall or short guys. Yeah, the guys who say that it depends on the training and the height has nothing to do with your skills are right, but only for the skills, not for the fighting at all. Your performance is based not only on your skills, but also on your size- height, frame and weight. Generally- taller you are, better you fight in any sport. But of course there are some limits- if you are too tall you won't be able to use the full arsenal of your combat sport. The guys who say that the mindset is very important are very right. If you like to kick, of course it is better to go for KB or MT, even if you have short legs and reverse- if you don't like the kicking, even if you are long legged, you probably should stick to the boxing.
The thing which, guys you, all miss is the weight and body frame and type. It is not just about the height, but it is also important to keep in mind that if you are with short legs, long arms, strong skull, big fists, skinny legs you are probably better for boxing and reverse. In my opinion the MT has more devastating weapons and it is suitable for people who don't have so much sheer power in the upper bodies. If you are fat and cannot kick, why you are going to go to fight in MT and KB? So these are some of my thoughts on the question.