T5 certainly looked impressive when I flew into LHR yesterday, but I can see a few problems here:

47 stands are being quoted; will this be enough for even BA alone at peak times? I’m 99% sure that they use more than that at T1/3/4.

Unrivalled access; hardly. By road you still have the fun of the M25 and the rail links will still be 3rd class. Why can’t they offer the same as CDG/AMS/FRA/ZRH? ie. direct long distance services.

Taxiways around T5 may be great but not really relevant when a/c still have to taxi past central area for a 27L/R t/o ie.right to the other end of the airfield.

The fact that it will take until 2008 for BA to get all their services into one terminal is typical; other competitors such as AF/KLM/LH and most US carriers have had this for 10+ years.