The uniqueness comes from the fact that the creature was piscivorous. It would be the only raptor in the game to have that feeding behavior. I would just ask the designers to go for a different looking type of design. Especially with their excellent work with feathered models.
What? Megaraptor isn't a raptor. It's a megaraptoran (I know, super helpful), a group that's poorly known and unfortunately difficult to pin down on the family tree. While they used to be thought of as carnosaurs / allosauroids, more recent analyses recover them as basal coelurosaurs or basal tyrannosaurs. I'm also not sure where the piscivorous diet comes from. Are you sure that you're not confusing Megaraptor with Austroraptor?
I think that having two species from the same family / clade can work well if there's a large enough size difference. As such, if they add another megaraptoran, I'd vote for Maip or Siats since those two are massive. Plus, with megaraptorans having characteristically long arms, they'd stand out well amongst the other large carnivores and might serve as a more natural alternative to the hybrids while keeping a smiliar general shape. Siats's exact phylogenetic position is uncertain though.
Even though we already have the megaraptor Australovenator in the game, I think that adding Maip or Siats (Siats's exact phylogenetic position is uncertain) would still add variety, as they are massive in comparison to Australovenator. Maip is 9 to 10 metres, Siats is up to 12 metres. Australovenator is only 6 metres.
I believe that is the smallest species yet found.
I would think that it wouldn't have been the only species to include fish in their diet.
I hope all those species are added. The lagoons are the part of the game that need the most work. Animal socialization and some sort of attraction. Archelon would be something totally new, that could add a fresh coat of paint onto that old wall, that is the lagoon.
