As I understand it, it is not the fact that a marriage is arranged that makes it invalid, but a lack of consent. If both parties really want to get married after an arrangement, I don't see why that should be a problem. If one of the parties is not free to consent to the marriage, then it would be invalid.
In terms of the number of annulments, Perhaps too many are granted now, but I think perhaps too few were granted before. Also, sadly and frighteningly, it may be that so many people hod erroneous or even heretical notions of marriage that many of them are not married.