Good for you. In which case, you're spoiled for choice in a genre that calls itself fantasy but has little to do with the fantastic. So you don't bloody well need another more of the same traditional rubbish. "And if you don't like it, familiar fauna is just a CD change, video store, or library away." Or even a short drive to the local zoo.
For fantasy, TES IV had Daedroths, Clannfears, Spider Daedra, Dremora, Xivilai, Scamps, and three very different varieties of Atronach. The traditional setting contrasted sharply with the invading Daedra. In Morrowind, many people didn't realize which creatures were daedra because they were all bizzare. Not a good idea for a setting where the Daedra are invading our world. And might I remind you that the only criticism allowed is constructive criticism, so please be more civil.
They were pushed into that by the fans who complained about the lack of fantasy wierdness in Oblivion itself. And to be honest, the things Shivering Isles weren't all that amazing. Sure, it was a great expansion and i loved it, but look at the huge murshrooms, we had those in Morrowind, the entire landmass of Dementia looks very simulair to the Bitter Coast region of Vvardenfell, Mania is a hippy Ascadian Isles region, Gnarls are a spin-off on Ents, Elytra are just huge bugs, Grummites, Scalons and Balliwogs are mutated frogs and most of the Daedra were already featured in earlier games.
Such things often work both ways. Kagouti, Alits, and Guar are spin-offs of various dinosaurs, Nix-Hounds are just half-dog-half-bug, Kwama are spin-offs of termites, Cliff Racers are spin-offs of Pterosaurs, and Netches are spin-offs of jellyfish.
What's hard is putting that stuff in a world and having it remain a cohesive setting that makes sense in relation to itself. That's why Vvardenfell was great and why Shivering Isles, though also original, wasn't the same. A plane of madness by definition need make no sense.
The fauna of the Shivering Isles varied from place to place to match whether they lived in Mania or Dementia. They're still mortal creatures that would have changed and evolved to match their environment.