The Goo has indeed evolved over the course of its time, from what it was implied as in Jon Spaights work, which is a Pathogen/Substance that allows for Genetic Splicing/Hybridizing and seeding of DNA
The AI element to it could be interesting as it means it can be programed to alter how it effects subjects.. i think this was brought in to allow for and explain why the Black Goo reacted differently in Alien Covenant