This is an archetypal case of evolutionism poisoning science. The man has done some good analysis and you'd be losing valuable information to dismiss his case entirely; particularly the idea of the large Neanderthal eye sockets indicating large, predator eyes and nocturnal-ism after Neanderthals became total carnivores in the ice-age environment. Likewise his reconstructions of Neanderthal appearances make more sense than what we normally see given that Neanderthal DNA is typically described as about halfway between ours and that of a chimpanzee. The claim of ice-age style long fur is also believable.
The theory involves the claim that Neanderthal genome data released in 2010 indicates that "Neanderthals had interbred with early humans from the Middle East ". Other studies which I'd put more faith in indicate that this never happened. Particularly James Shreeve's "Neanderthal Peace":
indicated that there was zero physical evidence of crossbreeding and studies on plos-biology's website indicate that the Neanderthal was ruled out as a plausible human ancestor because the genetic gap is simply too wide.
There is a problem with the idea of nocturnal predation 50K years ago for a number of reasons and the familliar gambler's problem which kills PE would also kill the idea of a dominant Neanderthal species reducing the planet's human population to 50 individeuals in one area and then that human species spreading out all over the planet and wiping the Neanderthals out all over the planet. In real life when a species gets reduced to a tiny group in a small area, it goes extinct.
Other than for the good catches on the large eye sockets and the likelihood of long ice-age style fur, Vendramini's theory may be BS but, as BS goes, it is particularly good BS and the sort of story which the popular media loves. I'd expect to hear more about it in the future.