I am playing v13 on Normal. I'm at the end of Chapter 4 trying to figure out Narcissa. I'm playing 100% vanilla.
I'm starting to enjoy the overall experience a lot less because of the constant need to use cheese tactics and hoping that I get a good RNG match. The fact that I am having to rely and consider on the RNG at all makes me feel that the balance of the game is not right. As of now, I have no ability to use the EV training facility, I can't buy revives, there's no reliable access to berries (that I have found), and I have not found any battle items that could influence my tactics. If the bosses/gym leaders have their optimized fields, optimized IV pokemon, fantastic movesets to counter anything that you throw at it, and are omnipotent/clairvoyant to the point they somehow know your items, when you're going to switch, even at the start of the game (and it only gets harder as you progress), then for a vanilla play through, players probably need the revives and access to better items at the very least. No one should be omnipotent either. I feel this would be where the game needs to be adjusted if the devs wanted to keep the specialized fields (which is something I like).
So far, the only change I have made game wise is that I went from 'set' to 'switch' to see if that could help combat some of the AI's ability to know when I'm going to use a different pokemon after I KO one of theirs. I did this to make an attempt to not rely on cheesing everything and test out different tactics, but it only helped with so much. TBH I'll probably drop the difficulty to easy just so I can have a good experience. If normal is this difficult, then easy should still see some of the same difficulties.
Edit: I would also like to add that I am incredibly disappointed that I can't even evolve the Feebas until halfway through the current content. If the forms are rare to encounter, it would be a delightful to be able to evolve a gift pokemon early since it seems like it could be very useful in some situations. That could be a nice quality of life change and a great way to reward players as they grind. I've put in almost 60 hours and I'm only at the end of Chapter 4. Who knows how long it will take me to get to the point where I can actually evolve it.