From what I have observes, most of people who don't like or have come a way from this game disappointed are the ones who keep comparing it to Xenoblade, despite the games being very different outside of the combat and open world.
I loved the cast and story from XC, but this game reminds that exploring the actual world and most of the quests were a pain. Makna Forest was eye candy, but I hated traveling it and had my least favorite music track in the game. Alcamoth is absolutely stunning, but I hated navigating those platforms and hated anything that made you swim. Valak Mountain is opened and empty, but beautiful at night and Mechonis Field felt more like a dungeon than a place where people lived unlike the other locations. Remembering who was out at what time was also a pain.
Exploration in XCX is fun and other it can be painful trying to find how to reach that treasure or navigate through a horde of high level mods and tyrants, it is all part of the fun. There is also more weight when you complete several normal quests and you decisions can have real consequences if you're not paying attention.
The battle system is also much better, no question about it. I know people loved changing party members to get a different experience, but you can do the same thing with your avatar. You can turned them into a tank, a dps, crowd control, ect. Yeah, it isn't quite the same as switching characters and there is no mage class, which makes since given the setting, but it is there.
The best way to decided is that XC is one of the best traditional JRPGs with several twists and a good opened world. XCX is one of the best more modern JRPGs with really takes the opened world and create a world that feels truly alive. Plus you control a giant freaking mecha, which changes the game.
Maybe they can blend the strengths of XC and XCX in the next game, but overall all XCX is ace and is one of my favorite RPGs.