Psychic has been nerfed into oblivion slowly but surely. In gen 3 it was balanced.
In gen 4 with the addition of so many good new steel, dark, BUG and ghost pokemon and moves, it's more of a liability than anything else now.
but if you ONLY take dark type in consideration...that change alone didnt do too much. and seeing that many dragons have insane BST...theres no fear that everything is going to be more unbalanced than before
Psychics back then was OP as heck. They had to create two new types specifically to nerf it. Gen 6 needs to introduce a reliable special fighting move that isn't Sacred Sword or Aura Sphere. A base 80 with 100 accuracy special fighting move would help Psychics a lot more.