The main problem with this essay is that it does not give a sufficiently clear initial definition of the language instinct thesis; it is therefore difficult to assess what the testable implications of the language instinct thesis are, and how those differ from what Evans presents as the agreed upon consensus of linguists:
Our brains really are ‘language-ready’ in the following limited sense: they have the right sort of working memory to process sentence-level syntax, and an unusually large prefrontal cortex that gives us the associative learning capacity to use symbols in the first place.Presumably a linguist already knows how this standard view differs from the specific implications of the language instinct view, but it wasn't clearly explained in the essay.
Also, Evans criticizes Chomsky's view about how the capacity for language evolved in humans, without making it clear that this is a separate issue from whether the language instinct theory is correct. Chomsky could be wrong about how the capacity for language evolved, even if he is correct about how this capacity operates.
Nevertheless, the essay is well worth a read by anyone interested in human language acquisition. I wonder whether and how Chomsky or Pinker will respond.