Not entirely sure why the plans are kept secret. There's no reason why they shouldn't be shown to staff. After all, they are pretty impressive and I think quite a few people would express an interest in what is being proposed. I was shown them in a staff meeting a few weeks back but other than that, nothing has been mentioned.
I totally agree about the lack of staff. We have the same problems in T2 most days and if the new terminal designs are to work efficiently, then they need to have decent staffing levels in place. That said, the redevelopments will see massive visual improvements to T1 and T2. New seating, flooring etc is all part of the plans and I believe that in itself is a major step forward.