If landing traffic on 24 has to backtrack the whole length of the runway to exit at Alpha then departing traffic being pushed back onto Alpha may be delayed in doing so. In that situation aircraft cannot "queue up" for departure on Alpha. Bravo, with its diverted centreline, can at present be used for arrivals in such circumstances but who knows how long it may be before that suffers more subsidence and becomes suddenly unusable.
I just cannot believe that the cost of rebuilding and slightly reconfiguring Charlie can be so great as to allow the current situation to continue. I hope that ourairport is correct and the matter is "in hand" to be rectified.