Well said michael - this crossing is counter intuitive and you'll often see people every few minutes fooled into thinking it is at last their turn and having to scamper back.
They are not stupid - it is just this crossing is different to any other.
It is simply very badly designed.

The count down idea is excellent, but unfortunately the countdown tfl want to bring in is to time people as they cross. This apparently encourages people cross faster and so tfl can further reduce the total crossing time.
It also encourages people to cross at the very end of the cycle. Not good.

As superior as your wait timer idea is, michael, we can't really have some lights displaying crossing timers and others waiting timers, without having a total rethink on how information is sensibly displayed to people.
An exercise like that is way beyond tfl's capabilities - they can't even get the basics right.