Though, I think that the evil ending in MotB is one of the best endings ever, however I didn't like the fact that all your companions (except One-of-Many) turn against you, if you choose to devour the Faceless Man. And I don't actually see the reasons for them to attack if you have *very high* influence on them.
So, my idea is - if your character has high influence on companions and devoured Akachi, then there should be added some dialog options with Diplomacy, Bluff or Intimidate checks to convince your companions to stay loyal (or at least not to attack).
10 - A Masterpiece, Genuinely Groundbreaking 9 - Outstanding, a Must Have 8 - Excellent, Recommended to Anyone 7 - Very Good, Deserves a Look 6 - Good, Qualified Recommendation 5 - Fair, Solid yet Unremarkable 4 - Some Merit, Requires Improvements 3 - Poor Execution, Potential Unrealized 2 - Very Little Appeal 1 - Not Recommended to Anyone