*New 3DS

And the New 3DS version won't sell better than the Wii version.

I think that it's going to be a Persona 4 Golden scenario in this case, where the port would outsell the original (probably thanks to digital sales, I could only hope that Nintendo doesn't cheap out on the copies this time around...)

I'll say a thing: the install base doesn't matter this time. Not with flagship titles like Xenoblade 3D is for the New 3DS.

Just compare the sales of OoT3D, a remake, to A Link Between Worlds, a brand-new game. ALBW came out when the 3DS had a much bigger install base and failed to outsell OoT3D. One could say this case is an exeption due to some things, but you have other examples of this scenario.

So, answering the OP: I think the 3DS version will easily outsell the Wii one. I bet it'll hit at least 1.5m LT.

Wii. And I find it funny that Nintendo thinks Xenoblade is a good launch game for the New 3DS.

3DS will sell more, I think.

Didn't they discontinue the game shortly after or not produce many copies even though the demand was high?

I think if they kept producing copies, the Wii version could have sold much better, but because of this reason I am saying 3DS

Very hard to say. Yes the Wii had the larger install base, but there were a lot of extenuating circumstances. Xenoblade Chronicles on Wii didn't catch on much in Japan resulting in it being delayed for the West and coming out in 2012 when it looked even more dated than it would have if it had launched on time. Also, it got zero fanfare coming to the west, no advertisement, no promotion, nothing. I didn't even know it existed until well after launch when I saw it on a store shelf. This was also at the end of the Wii's lifespan when the gaming core - who had been on board early on - had written off the Wii as a gimmicky casual device and stopped paying attention. The cherry on top was that it got a limited printing and was sold at one retailer chain.

The New 3DS version doesn't look like it will have to deal with that as it is a launch game for the N3DS, which means it's going to be pushed at least on some level and Xenoblade Chronicles X has put the series in the spotlight more so than it has ever been before.

With all that in mind, it could do more on N3DS, but it's not certain either way.

Xenoblade Chronicles on the New 3DS won't come close compared to what it sold on the WII ...

Despite having the stronger platform type brand in Japan, the audience over there wasn't fond of the game initially on the WII so nothing should change on that front. Xenoblade Chronicles on the 3DS in the West should have a harder time than it did on the WII since the frugal lineup makes it harder to adopt the new platform thus making it harder for the port to gain traction ...

It came out in the west in 2011. One year after the Japanese launch, which is fairly normal for RPGs that aren't from Square.

It makes sense if you have in mind people that want this game are dedicated gamers,willing to spend more money on a new system plus the game. Other audiences might be satisfied with the 3DS library already. With that said, they need more launch games for the system, or it will become pointless.

Japanese? xenoblade had way more sucess in the west.