I'd say the 3DS is the better choice for YOU personally, especially if you like Atlus titles. There are also new titles coming in regularly, including another Fire Emblem. That said, if Xenoblade is your main draw, it's sounding like the 3DS' game isn't as good as the Wii version.
The Wii U will be the better system for the family (it uses HDMI, btw), but its selection is far more limited and will likely remain far more limited. The Gamepad also may or may not be usable throughout the entire home: it has a theoretical range of 20 (30?) feet only, and that gets reduced the more walls there are between the Gamepad and the console. Realistically, you can play it a room or so away from the console before it becomes a potential issue.
Further, it'll be difficult, though not impossible, to track down a copy of Xenoblade now. As an aside, Wii games are NOT played through an emulator: the actual Wii hardware is crammed in there too, so there will never be any emulation issues for any Wii game. This means you can play any and all Wii titles as if it were on the original system.







