Nintendo is sitting on a pile of oppourtunity. That opportunity is called Tellius. Tellius is the setting of Fire Emblem Path of Radiance and Radiant Dawn. It is also(imo) the coolest universe in gaming. It is filled with interesting,well developed, powerful characters.

There's so much that Nintendo could do with this world. 

Imagine a DmC style action game starring Stefan. It could be called Vague Katti(After his insanely powerful sword)

A stealth assassin's creed/theif type game with Volke or Sothe

Or maybe a Griel Mercanaries game where you play as the Mercanaries after the events of PoR doing various missions

Blazing Sword universe > Tellius

They really might as well just make new IPs in that case, although the thread makes a good point that we only see the wide world of FE through these very impersonal battlefields.