My points on the subject...
If William ever was to fall in love with a catholic girl, the girl would more than likely know that she could not marry him still being catholic. So I would say she should change her religion. If she was unwilling to do that, she should give him up, as unfair as that sounds--I believe if someone really loved William they would not be so selfish as to make him abdicate, since he was born to be King. It would be very unfair to both of them.
Though, I'm sure William knows this and wouldn't put a girl through this sort of thing (giving up her religion), so I doubt he would date many Catholic girls.
I don't think they will change the law, because I read somewhere that they were going to, but there would have to be so many laws and parliamentary changes made that it would be very difficult. I do think that the should change the law, but I doubt they will.
My father is Catholic and my mother is Baptist, and I've chosen just to be Christian without choosing either walk, so I can understand what all the Catholics are saying. It really is more of a way of life than just a religion.