Patrick

The argument here boils down to "she had plot relevance." But the facts are that she was a villain who appeared and died and has little overall focus within her game (a game which, incidentally, introduced and killed at least four other main villains, depending on which ones you count as 'main'). Just because she was name-dropped into plot relevance in the last act doesn't improve her relevance to the overall plot of the franchise (to the degree there is one). One can just as easily write in other mentors or top-level Umbrella scientists in the same manner.

Wesker, by contrast, is a major focus of at least three Resident Evil titles. The story of Chris Redfield is directly tied to the story of Wesker, a thread that begins with the original game and doesn't wrap until Resident Evil 5. Let's not diminish the interest that Wesker commanded by suggesting that a document saying "trust us, she's important" puts her on the same level.

I'm happy to entertain the concept that she could one day become as important to the story as Wesker if she returns, but that's a distinct discussion from your headline.