>>57904366 (OP)This move looks like it has good theoretical uses.
But it has the same problem the Terrains had in Gen 6: Strong effects locked behind needing a move to set them. And then Gen 7 and 8 gave us Pokemon who have terrain setting abilities, and they were pretty crazy. Even weather had this problem before in Gen 2, and look how things are now with weather setters. I think if they released a Pokemon who set Gravity upon entering the field, it'd probably be considered pretty good.
If you want a genuinely bad move, I'm arguing Synchronoise, especially Gen 5 Synchronoise.