Your saying I Rex and indo raptor will get more play and make better AA’s if they are even added.No, it's not. The mosasaur he's a world-building, gun on the mantle in the first World, and a glorified cameo in the second.
I really do not understand the obsession with the creature. An AA version would be too slow (at actual size) to really be impressive. The only way it works is as a screen. And do you really want that?