Two of the really fun things about playing over ballad form is to be able to practice your lyrical phrasing, and your time feel. With so much space between the beat, and no backbeat to rely on, subdividing is extremely important for the soloist. And the same licks that can be played in slowly over a ballad can also be played in double time for a great challenge. A natural minor (Aeolian mode) will sound great throughout this form, but try switching to A Harmonic Minor over the V7 chord to bring out the tension notes. The G# dim7 arpeggio will also outline the V7(b9) chord very well. And you can never go wrong with A blues licks that come from the blues scale. 65 BPM.
Recommended Scales: A natural minor (Aeolian), A harmonic minor, D dorian minor, G# dim7 arpeggio, Amin7 and Dmin7 arpeggios.