These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Canon Sue: Meruru's a rather lovable, non-annoying version. Princess? Check. Everyone instantly adores her? Check. Ability to solve everybody's personal problems? Check. Personally responsible for the entire kingdom's future? Check. Heroic Self-Deprecation? Check, when she's not trying to annoy Rufus. Stronger than any of her highly talented predecessors? According to Astrid (admittedly, not the most reliable source), check. Plucky Girl who can achieve anything and everything she sets her mind to? Double check. Gets a statue constructed in her honour? Triple check!
Crowning Moment of Awesome: Everybody's super finishing moves. Double if you use them to win a battle, as each character gets a special theme for this and an altered attack sequence.
Les Yay: As usual. If you think Totori and Mimi going Les Yay on each other is enough in the previous game, try putting Meruru between them.
Surprisingly Improved Sequel: Generally the reaction the game's gotten on both sides of the Pacific. In Japan it was the highest-reviewed Atelier game since the original release of Atelier Marie all the way back in 1997 (until Escha & Logy took that crown, anyway), and it's the best-selling Atelier game in ten dog's ages. The reaction has been a little more varied among critics on the other side of the pond, but the high scores are among the highest the entire franchise has ever seen here by a county mile.
The Scrappy: Rorona. She got turned into an eight year old between games, acts her new age, and her memories have becomea complete mess. Though her Alchemic skills are still in tact, she mainly refuses to use it willingly. A very large portion of fanbase is not pleased. This is apparently because Gust couldn't stand to see her in her 30s. "Who wants to see a Rorona in her 30s? Not me, that's for sure!"
Astrid herself receives almost as much heat for doing the deed. Two of the endings make it worse! In one ending where you make a Youth Potion that restores her normal age, Astrid sabotages it to to only age her back to 14 with her memories still a wreck, with Astrid delivering the above message. In another, Witch's Tea Party, she forcefully renders all 3 Arland protagonists and herself to be 14 forever, citing it as an "ideal age". Some fans even treat the endings as the Moral Event Horizon.