Ha! So Fairy type is really. Funny... Back in the original XY thread, I remember there was a big 'discussion' about Light type/a new type and I was saying that Light type sucks and doesn't make sense, and brought up Fairy type as being something that was at least better flavour wise in regards to design/theme/etc. tl;dr I have amazing prediction skills.
Cleffa/Clefairy/Clefable need to become pure Fairy type, and I think the next obvious choice is Snubbull/Granbull (they are the Fairy Pokemon after all). Actually, I'm pretty sure most of the Fairy egg group will become Fairy type or at least gain it as a secondary type. Of those exclusive to the Fairy egg group: Jigglypuff already has (and by extension we can assume Wigglytuff), Chansey/Blissey (Normal/Fairy) and Audino (pure Fairy but probably Normal/Fairy) are other obvious choices and Plusle & Minun will probably go the way of Marill. Others that I see becoming Fairy: Castform, Snorunt (maybe Glalie, too, but that's weird), Cottonee/Whimsicott, Cherubi/Cherrim, Mawile (was this not mention in Pokebeach's rumours??) and Skitty/Delcatty. Togetic and Togekiss would probably make more sense as Fairy/Flying vs. Normal/Fairy. A few others I could see becoming retroactively Fairy or part Fairy as well. I'm hoping Celebi and Jirachi stay the way they are, but if they do have to become part Fairy than to drop the Psychic type or Grass or Steel respectively.
I like Noivern, he reminds me of a Digimon for some reason. Flying/Dragon typing is kinda strange though. Vivillon is a bit run of the mill, and I wish they weren't so lazy with it's 'arms', 'legs' and eyes.
The three new Pokemon revealed at E3: The blue crawfish is my favourite (re: me being good at prediction: I was at the zoo last week and was looking at some blue crawfish and thought it would be cool for there to be a blue crustacean pokemon). The evolved form of that cool bird is kinda strange though, it looks like he is wearing really high pants but that flame-looking design makes me think that it will be Fire/Flying. The coked out seahorse is interesting (Water/Poison?)... Reminds me of something from the Mario franchise for some reason.