"We have an entire group going on the Coral Princess Panama Canal cruise next April and we are all wait listed for traditional dining. The TA says our chances are good since we have numbers in the 50's because the numbers usually run into the 200's. That being the case, isn't there some message being sent that Princess is refusing to listen to? If this wasn't a group arrangement, I normally will not book a cruise unless I am guaranteed first seating."
You probably have a much better chance of assignment to "anytime dining" since it's unlikely that fifty seats in "traditional dining" will open up before your cruise if it's already fully reserved.
That said, with a party of fifty, it should be no problem to make a standing reservation for your whole party for the entire cruise at the time of your preferred seating in the "anytime dining" dining room. Your group will be large enough to occupy a whole section of the dining room, so the experience should be similar to that of "traditional dining." Be sure to call the reservation line when you first arrive on board so the staff will be able to accommodate your party.