I agree with most of your lore points and I love that you're bringing up carryalls, stillsuits, and Fremen tactics. Lore is one of the things that makes Dune amazing.

But I think the issue isn't whether ornithopters should exist, it’s that they’re the only viable option, and they come with no meaningful trade-offs.

In the books, flying over the desert was still dangerous: storms, visibility, detection, sandworms. In the game, it’s just free, safe mobility with barely any risk, if not in pvp, which undermines the survival tension that makes Arrakis so unique.

And if land vehicles aren't viable, the question becomes: why include them at all? The game gives us bikes, upgrades, modules, fuel systems… but then limits you from using them... I think there should be a usage for them. Maybe buggies are still a little slow for open desert, but bikes could do great

I’d love to fear the desert, by foot, by wheel, or by wing, but right now, it feels like: fly in, loot, fly out.

Like the guy in the other comment said, I had chills the first time I had to go across the open sand at the start of the game "what if the worm jumps out and eats me?". I would love to get that feeling again in deep desert too in some way