Oh I missed that. So we do more damage now due to how Defense Pierce work now, is what I'm getting... right?
And does Defense Pierce work for the magic and alchemy as well?
Yes, we'd do more damage (at least on 0 prot mobs), but remember that it's pretty much negligible when you're using skills like smash, fighter skills, etc... it's only good for normal hits. Just consider the effect like Tethra, where you wouldn't see too significant of a damage change when you're using smash (because who care about 30 more damage in smash lulz).
Plus, since the enemies actually have stats now, they get bonus defense and such. Devcat renewed the system so that we would still hit as hard as we used to (see more in the post).
And no, defense piercing doesn't work for magic. Monsters have their own magic def/prot now. And when mobs use magic, their "defense piercing" wouldn't work on us either. I'm not sure about alchemy, but I don't think defense piercing would apply to alchemy. Remember though, they get bonus from stats now, if you consider that as an alternative to defense piercing.