https://www.youtube.com/watch?v=po6B150CS_EThis video is about a week old, but it is very interesting as it gives us a ballpark figure of how many pokemon will available in the Galar National Dex.....and its not a lot.
It boils down to about 500 pokemon. FFS even if there were NO new pokemon in this game a whopping 300 pokemon have been cut from the game. However, there are new pokemon in the game, and if its anything like Gen VI and VII it will be roughly 75 new pokemon total, that means there are only 425 returning pokemon.
