I think a sequel CAN be as good as the first, assuming it's a true sequel and not a remake.
A lot of times sequels are made because the first movie was a success and the filmmakers want to cash in on a proven commodity. In many (if not most) of those cases, the "sequel" is actually a remake, in which the characters are essentially the same. SISTER ACT 2 and LEGALLY BLONDE 2 are both examples of remakes, rather than sequels, IMO. (LEGALLY BLONDE 2 _really_ illustrates this, because the main character starts it as ditsy as she was at the beginning of the first movie.)
Examples: THE GODFATHER, PART II and TOY STORY 2 were both true sequels. The situations were different, and the characters changed and grew based on their experiences in both movies. Same for THE TWO TOWERS and THE RETURN OF THE KING. They continue the story. (However, my wife hated TWO TOWERS because it was "too much war." She liked RETURN OF THE KING better, but FELLOWSHIP OF THE RING is, by far, her favorite, because of the sense of discovery.
To me, THE EMPIRE STRIKES BACK was a better movie than STAR WARS, even though STAR WARS was more fun. I thought EMPIRE successfully continued the story and deepened the characters; it helps that you had a fine screenwriter working on it. However, the same writer did RETURN OF THE JEDI, and I wasn't as pleased with that.
HARRY POTTER & THE CHAMBER OF SECRETS, to me, was bloated and boring, without the sense of discovery of HP & THE SORCERER'S STONE. However, I adored both HP & THE PRISONER OF AHZKABAN and HP & THE GOBLET OF FIRE because they developed the story AND the character, and kept the innovation fresh. I have high hopes for HP & THE ORDER OF THE PHOENIX. (However, after watching both THE DEVIL'S BACKBONE and PAN'S LABYRINTH, I _really_ want Guillermo del Toro to direct the last two Harry Potter movies!)
A lot of times sequels are made because the first movie was a success and the filmmakers want to cash in on a proven commodity. In many (if not most) of those cases, the "sequel" is actually a remake, in which the characters are essentially the same. SISTER ACT 2 and LEGALLY BLONDE 2 are both examples of remakes, rather than sequels, IMO. (LEGALLY BLONDE 2 _really_ illustrates this, because the main character starts it as ditsy as she was at the beginning of the first movie.)
Examples: THE GODFATHER, PART II and TOY STORY 2 were both true sequels. The situations were different, and the characters changed and grew based on their experiences in both movies. Same for THE TWO TOWERS and THE RETURN OF THE KING. They continue the story. (However, my wife hated TWO TOWERS because it was "too much war." She liked RETURN OF THE KING better, but FELLOWSHIP OF THE RING is, by far, her favorite, because of the sense of discovery.
To me, THE EMPIRE STRIKES BACK was a better movie than STAR WARS, even though STAR WARS was more fun. I thought EMPIRE successfully continued the story and deepened the characters; it helps that you had a fine screenwriter working on it. However, the same writer did RETURN OF THE JEDI, and I wasn't as pleased with that.
HARRY POTTER & THE CHAMBER OF SECRETS, to me, was bloated and boring, without the sense of discovery of HP & THE SORCERER'S STONE. However, I adored both HP & THE PRISONER OF AHZKABAN and HP & THE GOBLET OF FIRE because they developed the story AND the character, and kept the innovation fresh. I have high hopes for HP & THE ORDER OF THE PHOENIX. (However, after watching both THE DEVIL'S BACKBONE and PAN'S LABYRINTH, I _really_ want Guillermo del Toro to direct the last two Harry Potter movies!)