So when it comes to the amount of content in Duodecim or even the original Dissidia, NT comparatively has nothing in comparison, that being said I've had this game for years, bought it at one point for $14 because even if I didn't care for the beta, I figured it at the very least holds a lot of fan service(which is true.)
However, I wish I didn't wait so long to actually play the game and honestly wish I would have picked it up the second it received its first price drop and played it because this is actually a fantastic game if you can get past the fact that it's not the same Dissidia that you actually loved.
Now. I'm a huge fan of the original Dissidia games, with well over a few hundred hours in pvp in both of them. These are fantastic 1v1 titles and despite how unconventional as fighting games they are, they're my favorite fighting games. They allowed each of your characters to change skills for both brave and HP attacks and each of the characters could have three of each in both the air and on the ground.
Now NT has changed all of that. You cannot change brave attacks. Your brave attacks are all preset to add a more fighting game approach to this game and not allow any character to have multiple ways to approach a battle. These characters are now set up in a sort of predefined way. Cecil was my main on the original Dissidia and Duodecim and he was built around being a powerful character in the air as a paladin or being a powerful character on the ground as a dark knight. This has been changed a bit to where both characters are either air or ground based, but you have a cooldown that allows you to change between them, and the dark knight is built more as a medium range focused area guard or support character. The dark knight class is also very good at attacking summon crystals and enemy crystals because he can do a few quick powerful attacks and still stay at a distance. Not only that but he can dash and attack using a homing attack being further defensive.
It was when Overwatch released that the whole team based game kind of started. I don't specifically mean just "multiplayer" I mean games where you really have to work as a team which aside from shooters, there weren't a lot of games like this, and when Dissidia Final Fantasy NT released, not only were there only shooters and this, but this is also a game that was built from an orignal single player or 1v1 experience, not a team based experience. Even if it is similar to Gundam vs Gundam games(and I'd say that it did better than those did in the west.) This game was something I feel was just released too soon, when people weren't yet on board with the whole team based approach to video games.
These team based games now are a pretty popular genre, but it's too little too late for Dissidia Final Fantasy NT because once you release the game, it gets one chance and after that it's over. It's a game that was developed and released years earlier than it should have been. Square Enix wanted to be one of the first and they were, but it came at a cost. Not only did it kill the Dissidia series as we knew it, but the new team based Dissidia series never had a chance despite what I feel is an excellent game. This isn't just a game people wanted at the time and now they it's something they'd likely be more willing to accept.