I think I read somewhere that there were no plans to bring it to NA/EU because there are too many functions that are created for Japanese and would be hard to translate I want this game so much... why do so many awesome games never make it outside of Japan?
The DS instalment apparently sold rather well in Japan, but for some reason it never made to our shores. Perhaps Nintendo was afraid of this game not being well-received outside of Japan? According to Wikipedia, the first one got 29/40 from Famitsu, which is a fairly decent score.
I might be looking forward to Tomodachi Collection New Life and see if it would be a game I'd like to get on my Japanese 3DS. Still unsure, though...
So, the most recent Famitsu review came out, and the four reviewers gave this game a 9, making it a total of 36/40. Seems like that the 3DS iteration is pretty much better than the DS one.