This is just me, but I could care less about the debuffing effects of the Absorb skills. What my party and I care about is Initiation. Don't forget that you can bless as well as curse. The debuff bit is just a bonus.

I do agree that Poison could use some enhancement, but dropping a small Scourge before debuffing might also help. Most debuffs (Save Gravity, Dia, and Silence) are Umbral, after all.