I mean, they had two very different intents. FFXV's goal was to create a world that could realistically exist and support a human population, which is why you're only seeing a small portion of the continent you explore.
XC2's world makes absolutely no sense as a place where people would actually live (much less support an entire population and several militaries and full industry), but it looks cool visually.
I think the two games have some things in common in that regard to be honest, both fail to present the world that it is meant to be.
Xenoblade 2 tells you about villages and castles that you can't visit (because they obviously don't exist) and the titans are too small, the cities are still too small, theres no place for all the ships uraya should have etc. no big enough military harbours and i really wonder were the queen resides in uraya. It's all more iconic.
While Final Fantasy has a bigger world the major city is lost. You travel mostly industry complexes and pampa. Still the streets are full of cars, with people doing as nothing happened. Were do all those people live? In fabrics? While the second town is ok, it should be another country with a totally different culture, the game tells you so. And that's not the feeling i get when driving 5 minutes per car in a realistic way. Also the restaurant at the beach is called a town, where are all those guests coming from? the world isn't believable in my opinion and i could even live better with the iconic titans in Xeno 2 where you had to use your imagination. (Don't get me wrong, i really like the towns in Xenoblade 2 even when they aren't realistic).
The other continent isn't open world anymore, it works somehow, but i didn't have the feeling this was a great empire, but that's a story decision too. Also the best designed "town" wasn't visitable. In my opinion FF 15 fails miserable in comparison to old FFs like 7-9 with classic worldmaps when it comes to scope of the world and how good the places feel. The world isn't that bad, but it doesn't completely fit the story and scope it should represent. Breath of the Wild did a better job for me, even when the world is smaller and the transitions of the different climatic zones are hard. FF 15 sometimes feelslike a little schooltrip.
I wish for a new Xenoblade game that mixes the best of Xeno 1+2 with X. A really big and well designed world with distinct places and some well designed cities and different cultures, a good mainstory and the better sidestories from Xenoblade X. I guess they would have to spend a lot more money on that though. The same for SE.
If Tabata worked on XBC2 he would think this would be okay and an amazing idea.
It could have been a good idea if the game was manufactured around that from the start, some flying titans, island titans. Some "normal Ships". But you have to fill that with meaningfull content and i don't think they had the time and manpower.
