Nah, won't make a blind bit of difference to your speed because the distance from the DSLAM/PCP will remain the same.
The reason they want rid of the Exchanges is because they're to expensive to maintain and also BT don't actually own them. They sold them to Marconi back in the late 1990's after the who BT Cellnet disaster and then bought a 30 year lease on them.
That lease is coming to an end and Marconi want most of them back, not for the building itself but the land they sit on. There's already one Exchange they've taken back, I think it was in Kensington, London. No second guess needed as to why they want it back, The building and land it sits on will be worth tens if not hundreds of millions.
