Darius' E buff is not only unecessary, but it is pointless
- **Apprehend (E) **armor penetration increased from 10/15/20/25/30% to 15/20/25/30/35%
Between Conqueror,
, and his current E, Darius can essentially pretend that the enemy doesn't have armor.
This buff is overkill, and will only make a difference either in the early game (and even then it isn't that big of a difference) or against targets that stack ridiculous amounts of armor (think of something like Malphite).
I think Darius should not be buffed, he is already well balanced as he is currently (if not borderline too strong). The W buff will actually add power to Darius (extra power that he doesn't need) but the E buff will not make a difference besides encouraging people to ban Darius more.
But if Riot really wants to buff Darius, I would suggest buffing his Q, because it is peharps the least braindead part of his kit, given that you need to land the blade on his Q to heal and to deal the most damage possible.