Downside is, they become mandatory, like Aegis/Ochain still is for PLD. They are not really, but people make them a requirement, which is the same at the end.
I feel with everyone who made one or more of them, just to see them get dusty in your moghouse now. But at the same time I'm kinda happy, that i don't need to spend weeks or months to get a single item before i can bring a job to an event.

I still like the idea of such weapons, but if you want to make them so strong as they were in the past, then u need to set the difficulty to obtain them pretty high. Without the possibility of "cheating" like buying gil or making an army of Alt's.
They need to stay very rare.