Which is better on a Cordelia (+Spd, flyer) Life and Death or Swift Sparrow?

LnD is a good skill on any nuker unit in general. It helps that as strumplefluzel said, she is already really fragile. Therefore, LnD's buffs are more valuable, given that she would benefit more from +5 atk and spd over just +2 (or maybe 3 i don't remember what swift sparrow gives lmaao)

Defenses are overrated when they can be a negligeble loss. She could easily get around those with a mix of Desperation + Dancer/Reposition, Firesweep + Hit n' Run or just a mix of those.

Life and Death. She isn't living much in the first place anyway, and you get an extra 1 atk/spd