I'm not seeing anything that Katniss does to make her not a fighter or rogue or couldn't be done with those classes, outside of class based mechanics for inspiring a revolution (which ranger also wouldn't have). She sneaks around and shoots people with a bow. She knows natural hazards and lays some traps, which is using the survival skill or tool proficiencies. She applies healing poultices with the Medicine skill or Herbalism kit tool proficiency. Yeah, she doesn't use magic. She's from a world where it doesn't exist.
I don't think that's enough to base a class and 4 subclasses on when rogue and fighter already exist. Now, if you want to argue those classes don't get enough cool stuff and meaningful choices, I would definitely agree. And sadly the rogue appears weaker than the one already out now (though Ranger and Bard also appear worse to me), so I'm not holding out any hope that the fighter won't be more of the same garbage.
By this logic, Rangers should never have existed in the first place, because they're based on Aragorn, who does even less "Ranger stuff" than Katniss (quite a lot less), and also doesn't do magic.
You seem to be using an entirely circular definition of a Ranger, which is that, they have magic, and in order to be a Ranger, they have to have magic, otherwise they're just a Fighter.
It's completely and profoundly missing the point of classes. Classes exist to embody fantasies. WotC have said this on multiple occasions, note. They do understand that, at least conceptually. The fantasy of being "A Katniss type" or "An Aragorn type" is not handled at all by a Rogue, and not handled well by a Fighter.
Katniss' main thing is she's extremely skilled - Fighters aren't. Katniss isn't armoured. Isn't in the military. Isn't trained in any kind of tactics and doesn't have a wide range of weapons. But she's also not some kind of backstabber or Thief. And as you point out, she uses traps a ton, uses natural hazards, and particularly knowledge of nature (which her opponents are shown to lack) to defeat people. She knows and understands terrain and nature - something Rangers did in 5E, but no longer do in 1D&D, I note. Something Rogues and Fighters do not do. She's absolutely what people think of when you say Ranger. Even if you read the 5E description of a Ranger, she's a good match for 6 of 7 paragraphs (a far better match than with Rogue or Fighter, I note), with only the two random and out of place-seeming lines about Rangers knowing magic not fitting.
If we're at the point where we're denying people who obviously fit the pop-culture archetype of a Ranger are Rangers, just because they don't have magic, we can see there's a problem.
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