Overall the game is pretty good. It's got some flaws like a 3+ hour tutorial or at least what feels like a tutorial, and the gameplay may become repetitive, it hasn't been repetitive for me yet bit I can see it becoming more repetitive the more I play. I see some comments about it not running well on the OLED Switches so that may be something to consider if you have one as well as a lot of comments on the graphics. I'll touch on the graphics quickly, the graphics in this game are second only to pokken tournament they're really good for a pokemon game. If you were expecting BOTW graphics you have to consider BOTW was in development for 5 years, we don't know how long pokemon arceus was in development. Good things include a change to gameplay. I personally like being able to sneak up on pokemon to catch them, I'm glad there is no gym battles or champions, I think that it's great that is has a stronger focus on completing the pokedex, and I'm glad there's an increase in side quests. I've been playing pokemon since 2001 and I can say the mainline games have all become bland, this game revitalized the dream I had of pokemon when I was a kid being able to explore the pokemon world and to an extent do whatever I want in the game. It's not a perfect game but then again neither was BOTW or any other games I've ever played. It's a good game that branches off from the standard formula in a good way. I hope to see more pokemon games like it, they don't have to be the mainline games but they could be made every few years with a dedicated development team like how pokemon mystery dungeons was. My dream since pokemon gold and silver was an open world pokemon game with all regions and pokemon included where you're not bound by a story, there can be one but I'd like the main focus to be creating your own story without limitations on story progression. This is something that the pokemon company is considering since they released the game so I think it's important if we like this layout to show our support to the devs and prove to nintendo not all pokemon games need to be the same.
*Update:
I found out what people mean when they complain about "graphics" they do not necessarily mean the graphics themselves they mean the draw distance. Yes, pokemon legends arceus has a low render distance so that is something to be mindful when purchasing, I know some people have a huge sensitivity to images popping in and out, I have a family member who is like that and will get migrains from it, so if you're sensative to that type of thing I suggest only playing for short periods of time or to avoid the game altogether if your sensitivity is bad enough. Also I have a small issue I with how the game locations are setup; I should have realized this from the trailers and the screenshots that were released, but each location is a contained location, so there is no way to travel between them without exiting the expedition. I would have preferred it all be open to me and have roadblocks in the story to prevent progressing too early. So keep in mind the first area that you unlock is a contained sandbox and you cannot travel to the other location from there without leaving and choosing a new location. Aside from that the gameplay still isn't repetitive yet, it actually seems to have become more fun for me, if I notice any additional details I will provide more updates but over this is still a great game.
Update: Just beat the game surprisingly the last boss is easier that some of the one prior. Not sure why but for me it was pretty easy. I'd say my final review of 4 stars is pretty accurate for this game. It's got flaws but is a great game.