I cannot speak to why you did well on a high-carb/low-fat diet. I do not know the context of your high-carb/low-fat diet diet, your physiology, or the context of your life for that matter. I also do not know the state of your health/organs going into the paleo diet. Depending on the state of your health/organs, you may have a hard time digesting proteins and fats vs carbohydrates. I am not saying this is the case with you, but I suggest it simply as a possibility.
Not every diet works for every person, just like everyone has a different physiology. Roughly 10-15% of the human population can digest/assimilate the milk of today well. So for some that means dairy is nutritious, but for the majority of the population it isn't so nutritious, meaning that there are better sources for nutrition than dairy.
I will personally vouch for the "Paleo Diet" in that I do well on it. When I include large amounts of dairy or simple carbohydrates into my diet, I do not thrive. Personally I eat many carbs, but from fruits, nuts, and vegetable sources. I do not eat grains, legumes, and I also stay away from sugar. I also keep my meat intake a bit lower than most Paleo dieters. I strive to eat a vegetable to animal protein ratio of at least 3:1. I also stay away from seed oils, with the exception of coconut oil. I find a greater sense of mental clarity when I use coconut oil.
I also cannot say why most of the people here on cure zone do not get better from eating a paleo diet. But I do believe it has a lot to do with the physical, emotional, mental, and spiritual state of the people here going into the diet. What you will notice is that many here do not get well just from the paleo diet, but they don't heal regardless of the diet they use. And its not to talk poorly about the people here, as they are genuinely suffering and I take no pleasure in that.
If a person has conditioned a negative emotional response in themselves, and routinely thinks negatively, I guarantee that disease will come. I consider this to be much like a negative emotional & mental diet. Examples of this are effects in the body such as large amounts of c-reactive protein being produced, as well as higher levels of cortisol. So if a person has a ton of stress, no matter how good the quality of what they eat... it will have hardly any positive effect on their disease. Because the origin of their disease is in their mind and emotional reactivity, not in their food. You can often see the condition of a persons Mind in the way they post... frustration, anger, fear, intolerance, and arrogance are often very common with those that are sick. But the people that are healthy or are healing are often very positive, upbeat, and open minded.
This is why I mention the monks of mount hiei. A Positive mind offers positive reactions in the body, which I believe is compensating for the lack of nutrition in the diet.
I think the important thing though when it comes to diet is to listen carefully to our bodies and to keep an open mind. I think that is what you did Natway, and it is very respectable. Paleo didn't work for you, and you moved on... and tried something else. It doesn't mean paleo is bad, or unhealthy. It just didn't work for you.