Jux:
Torment realm chain RW doesn't give 30% boost. It gives a 30% field boost (compared to Gen 1 20% and Gen 2 50%), but it doesn't provide a stat boost the way Zack CSB or gen 2 chains do (or realm chains do later). So if you aren't already close to cap, boostga/faithga will help. But it will become less of an issue once we get the new soft caps, Magia, and Legendary Weapons.
And yes, not all of Torment Greg's attacks are piercing. But the only notable one is Critical, which is only a threat in Phase 2 because he uses that after a 99% gravity move on a character. In general, he has mostly piercing, gravity, or fixed damage attacks, so sub-30 teams generally forego mitigation in favour of more DPS.
