So Xenoblade did 83k first week.
Not really sure if that's good or bad. It's less than the lowest selling Xenosaga (ep3 at 120k first week) but when you look at how Nintendo published Wii games normally do with Disaster 12k, S&P2 11k, Regenleiv 27k, it seems kind of ok! I mean it didn't do as well as the Tales Wii games (~130k openings), but Tales is an established brand and this is basically an original IP given a quick no marketing release by Nintendo.
Maaaaaybe it'll be successful enough in Nintendo's eyes to bring it to the US and Euro and hopefully successful enough to keep funding Monolith Soft to let them make more 3 year development epic rpgs.
Apparently the highest selling Nintendo published Wii game that hasn't come to the US was Fatal Frame IV at 77k lifetime. So if XB doesn't come over it'll be their highest selling Wii game left in Japan. Which I guess adds a little more chance it'll come out in the US...maybe

I think the biggest hurdle is just that when was the last time
Nintendo paid $$$$$ for localization that includes like 5-10 hours of dubbing voicework required and thousands of pages of text? I can't think of a game of XB's caliber (basically a full size rpg) that Nintendo has ever localized. Since Nintendo loves making money and fears spending money I can't see them spending that amount.
*edit I was just informed they did that for Tales of Symphonia and Baten Kaitos Origins. So it's still very possible.