Not much has been said about the design of the new Shoreditch High Street station, least of all on this blog, so let's correct that.
Renderings like this have appeared on hoardings and in some promotional materials:
At first I thought this was just a conceptual picture of the line flying over Shoreditch, but no, they are actually building a five storey tall, quarter mile long windowless concrete box through the middle of the Bishopsgate Goods Yard site.
Here it is to scale with the enormous new Shoreditch High Street bridge (which you can fit a double decker bus under) and the even more enormous GE19 bridge:
The structure will have solid concrete walls and a concrete roof, making it feel like an underground station inside, despite the platforms being 9 metres above ground level. The brown bits aren't windows, they're "horizontal recesses that create a dynamic articulation in the façade when viewed as a whole", and will be filled with reflective material.
This letter explains why:
The enclosure will facilitate the redevelopment of the former Bishopsgate Goods Yard site by protecting the railway and station from future construction work. Unless the viaduct is enclosed, the future development of Bishopsgate Goods Yard would be severely constrained, or would require line possessions resulting in major disruption to ELL services. Construction of an enclosure to the viaduct is therefore essential if regeneration objectives of the boroughs of Hackney and Tower Hamlets and the London Plan are to be realised.It's expected the whole thing will be "virtually totally enclosed" with buildings in the "medium to long term". There's already a planning application in for the southwest corner of the site.
So yes, big concrete wall coming soon. The station planning application is here or you can skip ahead to this set of renderings and drawings.