They nerfed the piercing debuff because it's stupid, and they should have just gotten rid of it entirely.

SE is mortified of the DRG-MCH-BRD comp being good, so they balance DRG around the rDPS they add in that specific comp, and also balance BRD and MCH assuming there's a DRG, which is not at all fair to any of the jobs involved.

If you're a comp-obsessed group (which is foolish, but we know that a lot of groups are), and you have two non-DRG melee and a caster, are you going to take a MCH or BRD that's losing 150-200 dps out of the gate? You would have to need Refresh and friends awfully badly.

Giving piercing to BRD/MCH would be effectively the same as removing it - you could just buff all three jobs and it'd be the same result - so SE should either do that, or give it to RDM so that "have a DRG or RDM" becomes a comp 'requirement' the same way "have a SAM, NIN or WAR" is, and then assume its presence in the same way as well (i.e. don't treat it as rDPS for the DRG or RDM).