Actually 1h spec increases all of your damage, white melee, yellow melee, yellow spell, etc when you have a 1hy weapon equipped. That said having a more diverse spec is probably better unless you need to eek out every ounce of threat you can from your pally.

Aura will be resistance, concentration, armor or retribution. Usually retribution.

Blessing will be either kings or sanc. Kings for bosses, sanc for trash.