Hey man. As far as adding new pokemon goes, I wonder how good it would be if you added eevee as an obtainable pokemon to one of the pokespots . Also, re-organizing where some pokemon are obtainable (as an example, if you could catch the first evolution of salamance, which you don't obtain till basically the very end, i think that would be bagon right?) as either a shadow pokemon earlier in the game or a pokespot capture, it would mean people would be able to raise it as their own throught the journey, rather than capturing it late game to be used as a tank in the last battle or something. There's a lot of potential to increase the enjoyment everyone would get out of this game with re-arranging/adding new obtainable pokemon to the game, if done right, I agree. Also, it was pointed out to me by one youtuber that there is a serious lack of fighting type pokemon in the game. Maybe that would make for some good options.
Oh, and on the note of eevee, maybe it would be possible to add a few more stones in places? Just a thought, nothing that would unbalance the game too heavily.
Keep up the good work!
Sif