Fire Emblem's graphics worked for the 3DS, but I can't imagine it working on the Wii U.
Why not? (And by graphics, I'm assuming you meant art style) FE: Awakening's cutscenes were beautiful, and similar styles have been put on console games in the past, such as the Tales of -- series or Shin Megami Tensei stuff. IMO, the style would be fresh for the series, and it'd probably appeal to a wide audience now that anime is so mainstream. Plus, it'd allow for the in-game style to reflect the official artwork. Skyward Sword's artwork, both in-game and official art, is stunning. But, Link's model doesn't look quite as cool as his official art design. A style similar to what FE: Awakening has, only in Yusuke Nakano's style, would work just fine.
However, while that style would be nice, I'd like to see them work with what they've already started. I'm really loving that Twilight Princess mod that uses Skyward Sword's textures and colors. With something like that, you could have all those lovely, intricate and ornate details that Twilight Princess had EVERYWHERE, but it wouldn't look like it's been through the washer too many times. Lovely and vibrant and wooooooow!
OR maybe something between The Wind Waker HD's new style in terms of colors/texures mixed something similar to the Wii U tech demo's design styles. That'd be gorgeous.....
....But if it were my choice, I'd demand Ocarina of Time 3D's visual style. Perfect for the series, is vibrant and artistic for the fans who appreciate TWW and SS's styles while sticking to a less "toon" design that seems to have the fanbase divided. I think it's the closest to pleasing everyone.