(Continuing on from my previous post) In addition, having the characters from all the different FFs interacting with each other in story mode is something that a lot of fans have been wanting for a long time. Don't take this post as a flame. I'm just trying to help you see Dissidia in a more optimistic light.
As for Dissidia, do I really need to answer that? What's kicking a dead horse 20 years after it's died for you and maybe some others, is paying tribute for the 20th Anniversary of the Final Fantasy series for the rest of us. It's the only game that had references and characters to each of the mainstream FF games (except 13 and 14, seeing how they weren't out yet), it fleshes out the personalities of the protagonists and villains, it lets people see characters from every Final Fantasy fighting Advent Children style with psycho aerial battles and overpowered physics defying moves, and it's one of the few FF spinoffs that give a relatively equal amount of references to each FF (unlike Kingdom Hearts. It's a great game and all, but it's a bit ridiculous that there's only been one FF6 reference in KH2, when the later FFs got a lot more references). It's also got a story that has a really deep story for a fighting game.
