I would like to suggest once more someone else's proposal to tie in Fate Points with epic levels, and my addition to augment the amounts required for twists to compensate the limited amount of levels. Unless someone else has disapproved of this and I missed it, in which case I apologize for not reading any posts against the notion. Alternately, what about tying the points to favor with some of the epic-centered patrons, or obtained as a one-time thing through the completion of sagas?
Furthermore, imagine you do grind out all of your Fate points on your primary ED, and get all your twists unlocked first. Now, you begin to head through the other EDs, so you can reach the EDs of your choice and grind up the abilities you desire. Right off the bat, you can twist in a few choice powers from your primary ED, making the journey easier on you then for people who are going through each destiny to get their fate points.
To me, it would seem inherently more advantageous to remain in the primary and blast through content rather then plod along through other EDs. Hence my suggestion for some sort of balancing.