This is the final film in the Scream trilogy. As is usual in the third part of a trilogy, "All bets are off". Nothing that we think we knew after watching the first two parts is certain. New secrets are uncovered that contradict everything.
As such, this is the film that neatly wraps up the story. We don't need a fourth instalment, and we definitely don't need a TV series. "Scream 3" reveals everything that we need to know.