In reply to Bob:
Good bit of history there Bob. I think people should just accept the system how it is. There are obviously (with hindsight) more complete ways of grading a route but how far do you go? You can grade hardest move, overall difficulty, boldness, quality of rock and don't forget the star (quality rating) of the climb overall. But then it just gets silly, you'd be climbing a 5b-F6a-B1-5-***.
Obviously this is being extreme and most people may argue for simply a french grade with the addition of a grade for boldness, but then there are problems with this. People argue that it is difficult to grade the absolute difficulty of a move using an english tech grade, well yes it can be but this also applies to french grades. If a climb has a single hard move it can get the same french grade as a sustained pitch with lots of slightly easier moves. So in this way (if the protection can be assessed from the ground) then a uk adj + tech provides more information.
The second problem i could forsee with the addition of a french grade would be the potential for beginners to hurt themselves. Taking Bobs example of F6a = average E1. Would we really want people fresh out of the wall (where its easy to climb 6a) attempting to lead E1 straight away?
Due to the lack of bolts on most UK crags its appropriate that we have a different grading system to reflect this. It really isn't that hard to understand, and unless we really want absolutely all doubt on what a climb might involve removed why bother adding more grades. After all these new grades would not be any less subjective than the ones we have already.