It would seem a bit too early to release a replacement for the Em-1 but who knows, perhaps an Em-1s (or whatever) in order to better compete with the GH4 would be my guess in such a case. Which would basically mean an Em-1 with good video functions.
I'm not sure what it needs to compete with the XT-1 one more though, they both seem pretty level on paper, and in the reviews. With responsiveness going to the EM-1 and picture quality going to the XT-1.
I do agree that it is silly to have three cameras in the OM-D line, specially since they almost share the same picture quality and the EM-5 and EM-10 are very similar.
Then again, there would be no real meaning in releasing an EM-5 upgrade either as that would probably bring it too close to the EM-1 specs.
Personally, I do hope for an upgraded Em-1 of course as I am planning on getting one early next year.
Who knows, only Olympus I guess, we'll have to wait and see.