Honestly this is the first time I have ever liked all three Starter Pokemon, and from what I'm seeing in our other threads, other people really like all three of them too. I remember with D/P, everyone hated Chimchar at first, calling it a Charmander ripoff. Then with B/W, everyone's initial reaction was absolute disgust of ALL THREE of them, especially Oshawott. (I remember saying "I can't believe what I'm seeing - they're all just so terrible.") But this time, I honestly feel all of them are well-designed. In Gen I and II, Ken Sugimori did all the Pokemon designs, and many of them were simple and basic. With Fennekin, I really feel that simplicity - she's just some sort of stylized fox and reminds me a bit of Vulpix. Froakie reminds me of a Pokemon belonging in Ruby and Sapphire for some reason, I think because of how much R/S was based on habitats and how much a frog reminds me of tropical rain forests. Whereas Bulbasaur is a frog, Froakie is a more realistic take on a frog, just like how R/S took many simple Pokemon designs from past generations and made them more complex (like with Butterfree to Beautifly). Chespin is definitely the unique one of the bunch but at least he's not ugly like Turtwig or a semi-ripoff like Snivy. He sort of seems thrown together though, kind of how I and many others felt about Oshawott's appearance at first. But at least he's smiling, which Oshawott wasn't.
So Froakie has a sack around its neck, Fennekin has bright fur coming out of its ears, and Chespin has some sort of grass hat (almost looks like a Slowking's Shellder attachment). Could these be the three aspects of these starters that "grow" as they evolve?