If anything they'll most likely just Limited 3 it, meaning you still can run 3 copies, just not with any other Limited 3 cards.
Although......what the hell you even need 3 JD for? That's like asking for a brickfest. 2 at max is enough for an LS deck. Minerva can easily search it too.
Well like someone said on here before, that they limit cards that end duels too quickly. So yea, i see konami limiting JD to 1. We will see if my o.p is correct or wrong in due time
The problem is that not nerfing existing meta deck means that you won't spend money on purchasing new meta decks like Lightsworn. Then they won't be able to pay their employees to make even newer meta decks to replace the older new meta that you recently purchased.