Really some designs like Grimmsnarl, Corviknight, Coalossal, Sirfetch'd, Barraskewda, Dreadnaw and a few others feel right at home among Gen 1 through 4 designs
While some others like Stonjourner, Eiscue, Polteageist, Centiskorch, Dragapult, etc were clearly designed with a Gen 5-7 aesthetic in mind

This isn't about design quality, just design sensibility. There's a real tone clash this gen with a few designs being reminiscent of the older style and others reminiscent of the newer one.