See the main thing here a lot of fans totally focused on just the ending alone. But they forgot one very important detail just as the main characters forgot till it was too late (Really I should say they ignored that fact). Caius and Yuel repeated many times throughout the story that if you kill Caius you kill Etro, The goddess of the world. Yep. Not only telling them that changing the past also affects the future (In a rather cryptic nonsense way). But killing the dude that's trying to stop you from messing with time destroys the world. Maybe if Serah and Noel actually stopped for a moment. Talked this through and listened to one another instead of "You're evil you must die" attitude. This could have been avoided.
Don't bother bringing up that Noel didn't want to kill Caius nonsense. He didn't want to do it cause they were friends and it would make his girlfriend sad (No Serah isn't his Girlfriend. Its Serah x Snow remember. Don't give me that relationship crap). The problem was they didn't bother to listen to the important characters. Oh they listened to Lightning who as usual only knows half of it and just blindly follows orders anyway. (You have Valkyrie powers and the most you could do was fight...as a soldier....).
So why is it a great ending to me you ask? Cause for once in a very long time. The heroes don't get away with doing whatever they want. For once in a very long time the heroes actions bite them in the butt for not listening or talking things through. But for even better things. This storyline didn't conviently forget a character or event that happened. In otherwords no giant plot holes. Yeah there are some plot holes here and there but not big enough that require someone's fanfiction or massive fansite to take years at a time discussing what actually happened.
Am I mad at this ending of course not. This is one of the more interesting endings I've seen I'm a long time. Its not enough to convince me to buy this game however as I still hate the battle system and the game looks like a money pit with all of its DLC available. For other fans to be mad at this ending. They really should just get over it. A "Happy Ending" isn't required for every game especially "Disney Endings".