Only time will tell if it really is a personified Master Sword.
I kinda suspect this may be the end of the Master Sword, since Ganondorf was killed in TP and they may not feel they need it anymore. They got rid of it in WW, but it went out like a punk just being left on the ocean floor.

Of course it could be a far away land and a completely different sword. They seem like to release non-Hyrule games between the Hyrule ones.