Project X Zone is a great crossover game, seeing all the different characters from all the different game series interact is truly awesome. The one issue I have with the game is that it is too repetitive, has too many enemies to defeat per chapter, and is too long, in my opinion. But for what it is, it's a really great game and worth checking out if you know at least some of the characters in the game. Personally, I played it especially because of KOS-MOS and T-elos and wasn't at all disappointet with them in the game, there were a lot of great moments with them, and as a Xenosaga fan, it was wonderful to see them in this game. (It was also nice to see the .hack characteres)
I'd also like to see another Crossover game from Monolithsoft on the Switch, it's a bit of a shame that we haven't gotten any more since 2015, and Project X Zone 2 being the last one.