I agree there is good between platform circulation space in the newly built southern concourse, but there are limited passenger information screens up there except for next train, often though the next train from one platform may not be the next train to a specific destination. As I don't use my phone for online info much, I have found myself on wrong platform more than once for Brighton
That's not so much a station rebuild, it's basically providing extra screens.
Often the info is already produced, but cost cutting means screens that can be seen from every seat in waiting areas and along along 240m of platforms are not fitted, instead just token number of screens visible from limited positions exist.
Really busy platforms like Gatwick's need at least 10 screens along their length, both next train and the summary showing which platform for at least next 15-20 minutes (if not for next hour as some destinations are only hourly)