Great concept, but missing a lot of polish
Cons-
The world feels very empty and needs a lot more exploration opportunities. It feels like they just dumped pokemon into every space possible to make up for that emptiness.
Also, there is WAY too much talking, and it makes the game feel like it's padded with mandatory character interactions instead of actual gameplay.
If they had decided to put the time and resources into it, and make it a fully fledged explorable world like Breath of the Wild (which clearly it takes inspiration from) this game would be a MASTERPIECE. Instead, it feels rushed, and like a cheap money grab.
Pros-
The new battle system is much more dynamic, and requires a higher degree of strategy. (Good luck to challenge runners, because over leveling your pokemon isn't a solution anymore.)
I still posit that the battle system will not be perfect until it is done in real-time (like pokemon stadium. I think a battle system like the newer final fantasy games, where it's half real-time, half turn based, would be absolutely incredible), but this is by far the best iteration of battling I've seen yet.
Catching pokemon is much more interesting. No more brute forcing your way to catches with 500 pokeballs. Instead, each catch strategy starts from before you even engage the pokemon. Stealth and levels of distraction are now factors, and certain pokemon can be caught without even entering a battle, if you're smart enough.
CHANGING MOVESETS- This has been long overdue since pokemon red hit shelves in stores.
No more deleting moves, rather you can swap out the moveset that best suits your needs. Great addition
Conclusion-
Overrall, It's not really bad, but it doesn't live up to its potential. Given a few more years of experimenting with these new imemented mechanics, Game Freak may full well make the best installment we've seen to the pokemon series, however, Pokemon Legends: Arceus is definitely not that installment.