I was not disappointed when I woke up this morning. I'd like to share my thoughts.
Decidueye
Honestly, I hadn't found it all that interesting in the past. I simply saw it as an uninteresting Grass/Flying archer, but now looking at it again... It definitely seems like a fearsome Pokémon, in lore, design, and competitive. I'm definitely loving the ghost-typing to become more stealthy. Quite the interesting adaptation, if you ask me. I'm also liking how it loses weakness to Rock and some weakness to Ice. Its name is definitely something to appreciate too, as it comes from deciduous, which is a shrub that annually sheds its leaves and can even be a broad leaved shrub. This seems rather fitting, given Decidueye's broad feathery wing cape and how it plucks its feathers like leaves off of a tree. The only thing I don't like is the name of its Spirit Shackle. I can't help but feel like Shadow Pin or something like that would be better.
Incineroar
I can't really say much for this lug. I'm not much of a fan of Fire-types, nor am I a fan of Dark-types (with the exceptions of Yveltal, Umbreon, Victini, Reshiram and Darmanitan). It's interesting that it's Dark-type yet acts heroic... Hmm... Oh, and I can't help but feel like its giant hands help with it's Darkest Lariat, which I must admit, the move is pretty awesome.
Primarina
The beautifully perfect Water-type starter reveals itself to the world! I truly love this design completely! I've been in love with Popplio's line ever since I saw it in the E3 demo. Prior to then, I was simply going with Rowlet because bowties. When I saw that little ol' Popps had such good Special, HP, and Defensive stats, I fell in love. I tend to be the type to love pokemon that attack with Specials and can take a lickin' and keep on kickin'. Imagining Primarina with a possible 100, 70, 80, 100, 110, 80 stat distribution is amazing. Primarina has already become one of my favorite Water-types, rivalling only Vaporeon and Milotic. Primarina may very well be the only starter I select this generation. Usually I pick favorite then second favorite, but this time I'm just going full Primaria. I even plan on having my Moon version be a water-type only playthrough with shiny Primaria, my female trainer cosplaying her, Milotic, Vaporeon, Wimpod, Wishiwashi, and either Carracosta or Lapras. Oh my gosh, I cannot get enough of Primarina!! And that Sparkling Aria, too!! I can't wait to use that in competitive along with a high Attack pokemon! Take that, will-o-wispers! >: D
Tapu
I don't have much to say for the new Tapu, as I'd prefer to see them in the game before making opinions, as I feel like my view may very well change easily.
Cosmog
Same as above.
Alolan Persian
Honestly, when I saw it in the leak, I hated it. After watching a video explaining that it actually is like the real life Persian cat breed, I actually like it a lot. The actual cat breed is known for having a puffy, flat face and was bred to look that way by royal families and is an extremely classy cat, almost a status symbol for the wealthy. Alolan Persian is no different. It even makes it so the name makes sense, as regular Persian is a Siamese cat, even in its Japanese species name (which literally means Siamese Cat).
Red
I dunno what to really say about red besides damn did he age well. My god, I haven't seen a fictional character grow up to be so freaking hot since maybe Naruto...? But good golly gosh, if I lived in the Pokémon world, I'd seriously love to date him...! And, I swear, if they show him in the anime... Oh boy. Can't wait to hear his battle theme! And imagine him speaking the first word in 20 years! I imagine it could be him opening up to the trainer and telling him his story of adventure. I wonder if this means we'll see other past trainers...? I mean, Masuda and Ohmori did say there's gonna be surprises for fans of all generations in a way that hinted at something like this...
Blue/Green
Ok, I mean, I know his name is Blue in the US and Green in the Manga and Japan, but I feel like people shouldn't get so grumpy about his name... Anyway, Looking smug as usual, and easy on the eyes too! Glad to know he has a better sense of fashion than he did in FRLG! Well, then again, we knew that since HGSS came around. Wow, I realized this might mean Gary could cameo in the new anime like this. That'd be awesome! I can't wait to hear Blue/Green's battle theme though!
Alola Pokemon League
Ok, remember how the Indigo League had a name? I'm hereby dubbing this the Rainbow League because of the games' codename; Project Rainbow. I'm so excited that they added this. I'm even more excited for Cynthia! My all time favorite Champion returns in 3D and, hopefully, with a brand new remix of her encounter and battle themes! I hope I get to battle her with a full party instead of just 3, though! As for Wally... I think that's cool.