I feel like wildcards should just be reserved for dinos that show elements of all three classes or none of them. Some dinos within a class definitely have more affinity for that class then others (for example, both Thor and Purussaurus are Fierce, but Thor has far more fierce elements than Purussaurus), but I don’t see the need to add more categories. Even if Indoraptor was a cunning-leaning wild card, why not just make it cunning? The problem here (in my opinion) is that “wild card” is currently too losely defined and too broad, not that more dinos should be classified as wild cards.
That said, your idea still makes more sense than calling Monostegotops, Nasutoceratops, Pterovexus, Carnotaurus, etc. “Wild Cards”
By the way, according to one of the in-game tips, one of the ways Ludia classified wild cards was “being good in swap in teams”? I guess I see that with Monostegotops, but it doesn’t hold up. Phorusaura is phenomenal in swap in teams, so why isn’t it a wild card? For the record, it shouldn’t be, “cunning” is perfect for it. “Swap in” is just too broad and subjective to make sense. “Wild card” works much better as a description for dinos that embody significant elements of all three classes (like Tenontorex, Monolorhino, Thylacotator, Suchotator, Carnotarkus, and Purutaurus).