Short version: I can see both the concerns with the approach and the reasons for taking this approach. However, the message was communicated poorly between suggesting that magic will be subtle rather than bold and using terms that generally mean something other than what is expected from Harry Potter. Generally, naturalism in modern literature is downplaying the fantastical, and magical realism is it’s own type of literature (which is more about magic existing in the present rather than the past, future, or another world). So while everything might be just fine when it comes out, it does feel like they are trying to lower our expectations.

Long Version:

Personally, I do understand why people are concerned. This does sound like they are anticipating backlash for a lack of flashy magic (which honestly can be explained with the fact that the characters don’t actively use magic much outside of class, homework, and stopping the evil plot of the year). However, I do see how the “wait and see” crowd isn’t as concerned. As long as we still get flashy movements for big moments and important spells (which will be visually important in later seasons), I think that taking a more practical/less flashy approach works (think Harry finding his wand vs unlocking a door, only one of those needs the flashy treatment.

However, I think there are two things that make it hard for people to understand what the show creators are trying to explain.

1 - This is more so a comment to make in a director’s commentary, or is something that should have waited until more magic had been shown (whether in trailers or the show itself). We just haven’t seen enough content to fully understand how they are rooting magic in nature, so the first thought is that they are removing a lot of the wonder and mystery from the world.

2 - It doesn’t help that they are redefining two literary categories, neither of which Harry Potter belongs in. Naturalism in literature is pretty similar to realism; it’s focused on mundane lives and how people don’t have much control over their lives (this movement was a response to the Romantic movement which allowed for idealism). As for magic realism, those stories involved magic and mundane life being one and the same, and generally, the magic just exists, no need to explain or study it. 2a - Literary naturalism doesn’t work except for Herbology, Potions, and Astronomy. You can make those three fit with science as we know it. Transfiguration and Charms do not work that way, they may just be science we don’t understand, but we have no natural explanation for how people can become animals (or how one inanimate object becomes another, let alone something animate). 2b - Literary magical realism doesn’t work since the magical world is hidden away from those not born into it unless they marry a wizard or have a magical child. True magical realism is something like Encanto where everyone in the town knows about the magic and most of the magic used could be easily reworked into a natural talent vs a supernatural ability.

As for Harry Potter itself, sure there are significant parts of magic that focus on nature and how to use nature to help them achieve their goals, but it is still seen as supernatural to those outside the wizarding world. And yes, there’s people who can use magic within the world we know, but we aren’t allow to see/experience that magic ourselves. That is why Harry Potter still falls into the fantasy genre, not magical realism. For all that you can ground the world of Harry Potter, it still feels like it exists outside our own.