What to do with +Spd -Atk PA! Shigure?

It depends on what you look for with Shigure. When I summoned him way back in the Performance Arts banner with the exact same IVs, I decided I would try to make him a decent attack & dancer unit instead of a healer that most people make him. Believe it or not - he can be a dangerously lethal player on the field if you play your cards right... ESPECIALLY since his speed can reach insane heights.
For reference, this is how I built my rather insane Shigure:
Tome: Dancer's Score (+Spd) or Blárblade will be best.
Support - Sing (no exceptions)
Special - Dragon Fang or Luna (this is undoubtably helpful for him)
A - Life or Death 3 (In all honesty? He's not supposed to tank hits. Although his Res will suffer, too - you will appreciate it on the battlefield.)
B - Either Desperation 3 (full attacker, I wouldn't really reccomend it unless he NEEDS it on a certain map) or his rare B skill, which I myself use. Wings of Mercy 3 isn't so bad, either.
C - Threaten Speed or Res 3 (speed guarantees doubles in most cases while res will give him more attack power)
S Slot - Att +3 or Spd +3. I reccomend Attack in this case... but whatever works!

His normal psuedo-healer build is also a good choice IF you don't plan to invest a ton on him... or you want a non-Falchion psuedo healer. However... I heavily go against giving his B-Slot to PA!Azura. Urdr does a better job with buffing and she's better off having Wings of Mercy 3 or Escape Route 3 on her instead.