Well, I really have mixed feelings about this. Let's break it down:
We're returning to the Kanto and will have only 151 Pokémon and Alola Forms... WHY? I don't mind returning to Kanto a see it in 3D, but why include only 1st Gen? That's about 19 % of all the Pokémon (Not including different forms). Right now, I've used almost every Pokémon from Gen I and I have really hard time making some of my teams because I don't want to use same Pokémon over and over again. And Alola Forms? They're called Alola Forms because Pokémon from Kanto that lived in Alola had to adapt to the tropical settings. I can understand if you can get them with trade, but in the wild? Or will they come from the GO?
Next thing - wild Pokémon. It's been confirmed that you can only catch Pokémon, not battle them. I'm actually okay with that. I don't mind this in GO and as long as it's not in the core series, I don't mind trying this mechanic. But how will level-based evolution work? Please no candies. Also the overworld sprites looks great. And running into them for battle is also nice detail.
But even more important are starters. Pikachu and Eevee. Not that interesting starters. I would rather have Bulbasaur/Charmander/Squirtle trio. Let's break down the Gym Leaders and E4. Both Pokémon will do nothing againts Brock and you'll probably need another Pokémon before that. In Yellow, you can catch Monkey on Route 22, so I think this possibility will stay in these games too. Then is Misty and Pikachu wins there. For Lt. Surge and Erika is Eevee better but it still deals neutral damage. Next three Gyms are neutral from offensive and defensive perspective. And in the last Gym, both Pokémon aren't effective. In the E4, Pikachu can do something againts Lorelei and Lance, while Eevee is useless against Agatha. Stat-wise, Pikachu has 320 points and Eevee has 325, so it's not that big difference. So I have to ask... Who would use Eevee when it's pretty much useless for most of the game? Big plus for their customization, but it's one of the things that screams spin-off.
I really like Co-op idea, but the way it was shown so far really bothers me. In wild battle, the 2 Pokéballs just merge into one? How does that work? Wouldn't having double battle make more sense? Like one player catches one Pokémon and the other player catches the second one. And same applies for the battles. 2v1? Are we Team Rocket now? How could you enjoy ganging up on poor kids like this?
One thing that I'm glad to see is return of the Pokéwalker in the form of the joycon. It looks good and it's Pokéwalker! There is no need to anything else about it. Only minus I see is the price, as it costs just as the games itself.
I know I just jumps from one thing to the other, but now I would like to talk about connectivity with mobile's GO. Your Pokémon will finally have purpose. Yeah. But how will the transfer works? Will the transfered Pokémon have only 2 moves? And what are the items you can transfer between the two games? I feel like it can break both games. Like sending high IV Pokémon with high level to the Let's GO at the start of the game or sending infinite number of Pokéballs to the mobile's GO.
Last thing I want rant about is graphic. Why do the games look like something that was meant to be released on 3DS on 20th Pokémon anniversary? Why do they have chibby graphics from XY instead of the realistic graphics from Gen VII? I feel like they could do a lot more with it. And I really hope they won't randomly switch to the realistic graphics in the cutscenes like they did in XY and ORAS.
I hope I didn't forget on anything... Following Pokémon is nice feature, but I would prefer to turn it off (for some Pokémon) just like in the PR. And that's all folks.
Overall, I'm not really fond of the games right now, but will continue to watch them. I'm more hyped for the 2019 games and we know NOTHING about them. It's funny how GF is trying to destroy their own games. They did same thing with Pokkén on Switch (by showcasing Ultra versions) and now again.
I haven't bought Switch yet and right now, this game really isn't something that would change that.