It's really not that hard to tell which DPS is pulling their weight unless you have multiples of one class and sometimes not even then. Just look at the buffs on the party and the debuffs on the enemy...
Can you see Chaos Thrust and Heavy Thrust? Is the SMN DoT'ing, Baning and Festering? Archer using AoE's, DoTs and Bloodletter? BLM flaring? Do you see explosions regularly? You can even tell which MNK is kickass by seeing whether they change stances for certain parts of the fight.

You honestly don't need a parser at all.