I'm going to talk about the new Pokemon first...
Oricorio is so cute! And I love how its various formes each have a different typing. If they get good stats, I may get one, and ditch Pikipek and even Mimikyu.
Minior is pretty interesting. By the looks of things, it may also get decent Special Attack. In that case, Game Freak should make more special Rock-type moves.
I love the Fomantis line already, and if they get decent coverage, I may catch one for my team. Bounsweet, forget it.
Gumshoos looks pretty nice, but since it's pure Normal, I don't think I'll keep one in my team forever. But its totem form... It'd be nice if you could use that form yourself.
And then we have Mudbray, an adorable donkey! I hope it's obtainable early or middle in the game, and doesn't evolve by trading or something.
Now for the old Pokemon with Alola forms (which is probably Game Freak's version of Delta Pokemon):
Alola Exeggutor - While it looks pretty funny with its long neck, its new typing may make it more viable competitively. Now it needs some decent stats.
Alola Vulpix and Ninetales - While I was hoping for Fire/Ghost or something, they're very interesting! And Ninetales looks even more majestic than before!
Alola Sandshrew and Sandslash - Oh hey, it's the poisoned ice cream Sandshrew! And Sandslash... it looks like it's sick of the lower tiers, and ready to shine!
The Z moves are bound to be badass, riding your own Pokemon is going to be epic, and the Island Challenge is a nice and refreshing replacement for the standard gyms and Elite Four.