The most important principle of the justice system is fairness, so while the point you have made -- about the publicity of the accused allowing for other victims to come forward -- is certainly true, it has to be asked whether this overrides the arguments for defendant anonymity. The two main arguments for defendant anonymity are based around 1.) the fact that sex crimes carry a unique level of stigma that has a tendency to stick to those found not guilty, and 2.) the principle of fairness (i.e. if the accuser is to be anonymous, the accused should be also). The latter argument alone is enough to convince me. The current system, with its unbalance of fairness, is counter to one of the main principles of English jurisprudence, and it's important to remember that the accuser isn't supposed to have any advantage over the accused. If it's advantageous for the accuser to have the possibility of other victims coming forward to back up his or her story, it is unfair that the accused isn't afforded the advantage of the publicity of the accuser's identity encouraging witnesses to come forward with evidence that be useful to the accused's case.
But no matter how good a case is made in favour of it, it'll never happen, such is the aggressiveness of the lobby against it.