The thing is that while the game has quite a few flaws, they're mostly genre tropes, the kind of things JRPG fans shouldn't have much of an issue with.

As someone who is generally not a fan of JRPGs, there were times when it drove me bonkers, but on the whole it was worth it for the times when it does shine.

X looks like a more polished game, I'd go with that.

X is definitely more polished.

Having said that, I would still say XBC2 is the better game.

X is a more consistent experience in that it has fewer lows, but also fewer highs. It's more technically polished, but it never hits the narrative and musical high notes that XBC2 does.

I have played a lot of them, this is one of the few that have frustated me as much as did.

I’ve played both over 250 hours. My preference is thoroughly Xenoblade Chronicles X, as while I really enjoy the adventure of XC2 - it’s missing the vastness, the freedom (knowing that if you see it, you can go there), and the feeling of permanence - as in, I feel like a part of the world of XCX, something I don’t get from XC2 even close to as much. XCX to me feels like the more progressive and advanced game, while XC2 is more like a Xenosaga. Don’t get me wrong, I enjoy XC2 quite a bit as well, I wouldn’t have put all that time into it if I didn’t.
XCX has two major flaws though, 1. Its UI looks like a PC game. 2. It’s on Wii U.

XC2 is definitely more for beginners though. It’s VERY linear and handholdy like the first Xenoblade and the Xenosagas.

XCX is the wild west, you’re given a gun and a knife and you have to figure out on your own (with very little handholding) how you’re not just going to save civilization, but thrive in that world and make your place in it. While there’s some general bottleneck plot points, few people will experience the game the same way as each other. That’s a bit of a brief as to why I ended up so much more attached to XCX. Also, I like the story concept more than XC2: a city from Earth plunked down on an alien planet with alien humanoids and indigens - and you basically pick your role in society - the major conflicts which mostly revolve around your city - there’s a lot of mechanics and world elements that help lead to some emergent storytelling; but also a lot of built in sub-plots which all surround the development of spciety in these given conditions from many different angles. XCX is unique and much more appealing to me.

Aside from UI, and the fact that it’s on Wii U - the fact that Mitsuda wasn’t hired for the music feels like a flaw. They got some bigshot anime composer to do the music, and he REALLY didn’t know what he was doing with videogame tracks and made so much loud music in the game that it gave me a headache. Mitsuda opted for breaks with more ambient sounding stuff, and more strategically placed themes... although I do admit I got sick of several of the field themes - I think all daytime versions - luckily with XC2 you can control the volume of different types of audio.

Controversial - but I like the Breath of the Wild approach to audio better than any game I have ever played before, a strong focus on the atmospheric sound and music for appropriate locations and dynamically attaches to various triggers in areas, characters, and events. Very sparing on loud style music, though it exists for all the right instances. I found it as immersive as I found organic. I bring up Breath of the Wild because the game is closer to XCX in style...

A. It was minimalistic in the UI department.

B. It’s on Switch 

C. It BLEW it away in the audio department - basically the polar opposite philosophy.

I love both for different reasons, If I had to choose... probably XC2. Cant go wrong with either if you enjoy the genre.

Depends on your taste. Xenoblade series is about characters, story and JRPG soundtrack, Xenoblade X series is about open world, gameplay and Western themes. If you love P5, then it is obvious which game will suit you a lot more

If he love JRPG with deep story and fantasy themes as well as JRPG soundtrack then he can only choose 2

I am in a situation somewhat like the OP, but my question is rather : Should I buy a switch to be able to play XC2?

I have the orig XC and love it. Never completed it and maybe never will, but it is excellent and one of my fav games ever.
I also have XCX - actually its the reason I finally bought a Wii U (XCX edition as well). I also love XCX and cant believe how it was possible to make that game work on that hardware. I bought a couple classic nintendo games for the Wii U but never really played them. I respect nintendo for their craft of making excellent games, they just arent for me.
The plan was to get bayo 2 for the Wii U but still havent bought it (have bayo 1 on ps3)
So is XC2 worth it to get a switch ? Thoughts?

No console is worth it for a single game, but the Switch has an amazon library of games. Recently it’s been just ports, helping you to catch up if you didn’t buy them on Wii U, but upcoming games look so promising so research if you are interested in any other game.