While I agree that the complex sentence parser was sort of an achievement at the time, I don’t think it was that important, and certainly not influencial. I can’t think of a single mainstream game that came out in the last 15 years that used such a system, except for infocom games, which by the end were not really mainstream anymore. In fact, games that require simple text input are hardly ever seen, let alone the ability to type in full sentences.
I want to point out that I do like infocom games, and I’m not trying to bash them, but I just don’t think they were influencial or technoligicaly important. Early Sierra games were.