"could be really"? Perhaps I'm misunderstanding your use of those words - this is from 2007, and everything from the course is on that page, including videos of the lectures.
I interpret that as based on the portion that the GP has consumed. Like eating a 3 course meal, if the starter is great you might say 'this meal could be really good', you can't tell for sure because you haven't eaten all of it, hence the caveat.