Tigs2, you asked....
What is being done to help you guys cope with the huge number of Human Factors issues?
My answer..........
I think you get my drift....
In itself, T5 shouldn't cause too many problems. In fact, many people believe it might solve a few, such as number of stands (despite the fact that as soon as T5 opens, more development work is going to begin elsewhere on the airfield that will mean an overall reduction in the number of stands for the foreseeable future). There are rumours that BA will want to move all their nightstopping a/c from T5 to their maintenance areas for the night, and back again to T5 for the morning.
The taxying problems will come when BAA want to utilise the capacity that T5 gives the airport in terms of pax, and mixed mode is introduced. I believe we're going down the road (if it's introduced) of northbounds off 27R, and southbounds off 27L etc. This will work for perhaps 20 minutes, but then I reckon the whole airfield will grind to a halt. Bear in mind that there's an a/c off T4 trying to get to 09L holding point, T1 traffic going for 09R, and a/c landing on 09R wanting to park at T1, against a/c landing on 09L wanting to get to T4. More crossings of 09R/27L will be needed, which will in effect take up one 'slot', so the figures for that runway might actually be less then in segregated mode, where now we wait for a natural gap (vortex) to get stuff across. When we're single runway, we're taught not to use the outer/alpha adjacent to that runway, as a/c need to vacate the runway quickly. So you can just imagine that Ground will be a nightmare.
Tigs2, check your PMs