I really don't see what the obsessions with new types is. They are not at all needed and the types being raised just seem pointless. Light type? Dark was introduced to counteract Psychic. There is your counterpart, so no need for that there. And Sound type just because the theme of Light type is lurking around? They are pointless and unnecessary. I'd love to see the type charts get a re-vamp, just to make Poison a little less shit, but even then that's not even that necessary. They'll introduce new moves with new effects that'll completely change the current metagame more than enough to not warrant new type introduction.
As for the new looks of the Pokémon, I personally quite like Zoroark. There are a lot of pre-existing Pokémon which look a lot worse than he does. While the Gen 1 Pokémon will always hold something for me, even when they were new there were some Pokémon I literally couldn't stand and still don't. Hello Mr. Mime and Jynx! Three generations have came since then, and while I don't like some of them and others don't feel like Pokémon to me, nothing will ever beat my resentment for those two.
I still think the big change isn't going to be the battles, or new types or anything crazy like that. It seems to keep being forgotten about but the usual story of 8 badge, Team Blarh and then Champion is as big a part of Pokémon as the types and battles. If the main games were to get a proper story re-vamp, then that'd make you think, "Wow, was that actually Pokémon?". That is where I see the big change coming from. We've seen, all be it, a glimpse of the battles with Zoroark and friend and it looks pretty similar to what we have already. I also think if new types were going to be introduced, they'd play a part in the movie and they'd be the poster child of the 5th gen, rather than Zoroark. They use the anime (movies at least) a lot more than they did for the games back when they were introduced.
My gen 5 wish list is as follows;
1. Better Poison type (SE against Water and Fighting?)
2. Stealth Rock taken down a peg. I like my Fire and Ice types and would like to be able to use them.
3. A plentiful and origional in game story with as much to do after as Johto has.
4. Magmortar with a Fire equivalent of Motor Drive. Fuck Flareon!
5. Better Wifi. While the Giratina, Dialga and Palkia filled teams on the Wii are a treat, the option to get random battles but different areas of the game only allow certain Pokémon. Sort of like the battle tower ban list, but with a team of 6 and the ability to use more than one leftovers.