There's at least a couple of huge reasons why it was so epic outside of the obvious visual flair. One was the fact that it was an inevitable war that we saw happening before our eyes, which involved characters that we grew attached to and in that one case... unexpectedly lost. The other was the fact that it was an ending to an MMORPG, which is something that never (or rarely) happens. And yeah, watching our side essentially lose despite the best of efforts to beautifully dominant destructive power (... Bahamut) certainly added to the epic feeling. We're not used to losing.
