I doubt that just because pets attacked, we'd all start abandoning the Alchemist. I came from a server that allowed pet attacks and skills: there was no shortage of Alchemists there (I was one myself). Bomb and Acid Terror anyone?
However, the Poring argument has merit, since no one has autoloot here. (to protect Whitesmiths) People will still have alchemists, however. They carry a whole lot more stuff and with bomb, can do a great damage and the homunculus can evolve, whereas, pets only have 1 look. I think you are underestimating the Alchemist here. "Half a reason" is exaggerating, it's more like "1/3 at MOST"