Some interesting points raised here and as pointed out, BA are very aware of the issue and are looking at what can be done. Most passengers don't like it and we as staff don't either. However being realistic, it won't change overnight.
Some of the issue raised here have been interesting. First off, no matter how modern the design, the simple fact is that no terminal at LHR or most UK airports could support 100% on pier departures. There simply isn't the space to build large enough structures to do this. One reason T5 is taller than other terminals is due to limited space available.
BA isn't the only airline at LHR with coaching arrivals and departures. However, being the largest airline, BA will have a larger proportion. This number will thankfully decrease significantly when T5C becomes operational. KL used to frequently have coaching arrivals and departures in T4, but now there is plenty of space there until other airlines arrive. Same for Qantas, SriLankan and even TAM. BD used to in T1 and possibly still do, as do many airlines in T3, again, airlines with larger operations there are likely to be the ones most affected, but I do know that VS certainly does for one.
Introducing private cars for F passengers isn't practical. This could add to the congestion already felt on the airside roads, particularly at certain times of the day. In addition, this would then be used by the media to highlight just how much more polution BA was adding to the environment and give the environmental lobby even more reason to fight further development at LHR, by claiming that EU standards aren't being adhered to. BA has done lots of work in recent years to try to combat this claim, largely by using electric tugs, less poluting buses etc.
On another couple of points raised here, priority boarding should always be offered on all on-pier departures and on longhaul, there should always be a fast track lane. If it is not done, then feel free to speak to the team leader and if there is time, even ask for a duty manager or write in afterwards giving the name of the individual. We have been reminded many times and only if customers start complaining directly and giving names of the team leaders will things change. Be asured that when I am in charge of a departure, priority boarding is always adhered to.
As for connections, there are premium customer service desks there and there is a fast track lane for the ticket presentation/ready-to-fly desks that are manned by BA staff for interenational connections. Unfortunately, after this is the security check and this is where we have had many issued with BAA not properly enforcing priority lanes and manning them. This continues to be raised by BA with BAA, but this happens at very senior levels so can't comment on exactly what is happening.