This is just not true, we have statistics available publicly after all.
If you nerf Picto by 8% overall, it'd drop to or just above Black Mage, Reaper and Ninja in rDPS, but below Dragoon and Monk.
In Savage this would drop it to just below Reaper, but still the entire "gap" (~6%) ahead of the 5 utility-burdered jobs RDM, SMN, BRD, MCH and DNC.
So in other words, in Ultimate it'd be very marginally stronger than it ideally would need to be (ideal nerf ~10%), but in Savage it'd be very marginally weaker (ideal nerf ~6% or 7%).
Consider how tiny a variation that is. We're talking 2% DPS difference in either direction. It's an absolutely negligible amount considering how trivially it can be achieved (cut all potencies by 8% across the board). And that's assuming one would even use an overall nerf, like I said before the smarter way to achieve this 8% reduction is an ~14% nerf to the Muses + Starry + Drip + Holy + Comet, because this affects the downtime-gain very slightly more in the final result than the straight casting setup, meaning it'd be more like 9% in Ult and 7% in Savage. But again, that's not even needed. Considering how Reaper and Ninja and so very much aren't hardblocked from Savage, someone else dealing their damage while being highly mobile and bringing a raid buff like them isn't going to get blocked, especially because the caster alternative (Black Mage) comes with the moody attitude you always get when you let a black mage into your party. :P