Or, since Nimoy is semi-retired from on-camera work, are they writing themselves into a bit of a corner? “Once you kind of realize the extent of everything, it will probably become clear why we’re not [writing ourselves into a corner],” Wyman answered, cryptically.
My guess: Bell has soul-magneted himself into Walter, and both he and Walter are inside Walter now. (Which would explain Walter's personality change; and Walter's rage toward Bell is a cover-up.)
The EPs stopped short of confirming buzz that Season 5 would heavily involve the year 2036 seen in Episode 19: “That future is important to our storytelling, but it’s the not the be all and end all.”
My guess: Alternating episodes of present (or near-future, ie 2016) and future (2036). One set of episodes explains what happened to result in "Letters of Transit," the other set shows them fighting back in 2036.
“Seth is spectacular and awesome … but as for his standing going forward, to say anything about that would be also to reveal things that are coming ahead,”
My guess: The Alt-U will be seen again, either in the near-future or the far-future.