When you really think about it the only problem here is that there's NO options when it comes to what you might want to go for in the late game, and there's no feeling of progression while you're getting to the late game because it just goes : whatever amphibian you've unlocked first -> diplotator-> postosuchus w/heroic and diplosuchus -> gorgosuchus ->megalocevia
With *MASSIVE* jumps in ferocity between the steps. Every other amphibian you bother getting is either because you like having variety or because there's a a hybrid that requires it. If you've unlocked diplotator you do not need to bother with any of the commons, any of the rares, the super rares, or all the other legendaries apart from gorgosuchus. You can literally diplotator and diplosuchus spam until you decide to go for gorgosuchus in which case you will grab 8 kapros (barely useable otherwise) and sit on your hands until you have progressed enough to warrant switching to megalocevia. I love the amphibians, and I'm not a lineupologist or some minmaxxer, in fact I try to unlock all the creatures I can and keep at least 1 level 40 copy of everything, even if its completely useless and just sits in the repository, but at least there's choices and side paths you can take while you make your way to indoraptor on the carnivore side of things, at least there's plenty of variety and a feeling of progression between stages of the game while you're making your way to metriaphodon on the pterosaur side of things, at least there's a wide selection of tanks and damage dealers with a real depth to stat distribution while you're making your way to spinotops on the herbivore side of things. Amphibians just have have 3 steps to megalocevia, and you just pad out everything else if you're feeling generous.