I'm not qualified to comment on sizes, colours, fonts and the like (they do indeed appear to be standard, and some could certainly benefit from being bigger), but the placement of the signs - or lack thereof - leaves a lot to be desired.
That they've had to employ dozens of people to stand around handing out maps and telling people which way to go says an awful lot, I think. I expect it would have been much more confusing if I hadn't entered from street level with a good level of familiarity with the fixed infrastructure of the station.