I'm generally not a big fan of NG+, because for me a game is finished when I've played through it. But if this trophy already exists, then there are two points of view:
On the one hand, I'm happy if I know what's in store for me when this trophy is available immediately, and not months later (when I've already put the game aside). But it has the disadvantage that it is necessary for platinum.
On the other hand it has the advantage that NG+ is not necessary for platinum if it is supplied as DLC, which is an advantage for all those for whom 100% is not so important and only want platinum.
But in the end it doesn't matter to me, I want to have 100% if possible. I would like it best if there was an NG+ mode, but no trophy for it ^^