Ayaz Amir @ The News

Saroop ijaz @ Express Tribune

Cyril Almeida @ Dawn

these columnists consistently produce awesome stuff, though i am afraid they wouldnt fulfil your condition of being "unbiased".
Personal preferences & dislikes of almost all the columnists can be detected; some are anti army (K shaf) some are army apologists (Ejaz Haider) & almost all of them nurse a soft corner for one or another political party..