I just got Xenoblade Chronicles 2 and am wondering if it makes sense to get the Expension Pass already from the start or rather wait before I finish the game.

What I am concerned about is that it makes the game too easy or that it adds some unneeded items that stick out of the original story/feeling too much.

Is that the case, or is it rather just ironing out some small nit-picks and the DLCs make it better?