Perry, Aborigines are smaller than Caucasians. There is going to be variation within a species. As far as their adaptability to their environment is concerned that can be expected since they've been raised in it.
As far as their having more skills than us that is because we're the product of school education and further more we are not submerged in an environment from which we get our food. That is their 'profession' so to speak and evolution would have weeded out those who aren't smart enough.
As for Neandertal and his brain he had, as I previously stated less frontal cortex due to the sloping of his skull. That is the portion of the brain that deals with fore planning. However he had much more of the occipital brain, to the rear where visual processing occurs.
As far as tools are concerned it is undisputable in the scientific community that they did not compare with Homo Sapiens of the same time period. Just because it would be hard for you to make those tools doesn't mean that they're more intelligent than you. The reason is because they would learn those skills as children. It's like learning a second language, childhood is when it's best to do that.