Regarding the long interchanges... were there ever any plans published at the time that Crossrail was being designed that showed the intended station configurations, allowing the public to comment on them? I don't remember any such public consultations. On the one hand, it would seem odd if there weren't any, but on the other hand, it would seem equally odd if there had been public consultations and the question of convenient interchanges hadn't been raised at the time.
Last night I changed between EL and Overground at Whitechapel. The interchange there isn't that bad, but it still felt longer than necessary because it's right at one end of the (very long) EL platforms, so you have a long way to walk if you're at the wrong end of an EL train. And it seemed strange that from the Overground you first have go up the stairs in order to get to platforms that are actually below you. To my mind, it raises questions of: Why couldn't they build the EL platforms a bit further west so as to give better interchange, and, would it have not been possible to have a concourse at an intermediate level between the two routes (maybe that would have been too expensive?)