I am pretty sure that magic weapons in ACOTAR are legendary artifacts, not +1 moonblades.Were I WotC looking for a setting to liscence, I would go for Prythian, the setting of the A Court of Thorns & Roses novels.
It feels like a world that's roughly on a D&D-scaled power level - there are legendary monsters and super-powered spellcasters, but a highly-skilled human fighter like Jurian can still hold his own. It's got a large variety of both monsters to fight and humanoid species to play as.
The protagonists in the novels are already doing a lot of D&D-like things. They go on quests, fight monsters, find magic items, and learn spells.
But it's also distinctly not a D&D setting. The world-building in it is laser-focused on the various fey, and it's all got this twisted-fairy-tale thing going on. So it would feel distinct from D&D's in-house settings.
And, as had been pointed out up-thread: the other crossovers WotC has announced have all been properties that appeal firstly to middle-aged men. And they're nostalgia properties. ACOTAR is newish and current, and its fans are mostly women.
Also this would be the chance to implement masterwork weapons. By which I mean, they'd have to implement masterwork weapons for game-balance reasons, because magic weapons (specifically weapons, not other kinds of magic item) in this setting are basically inaccessible and an enormous deal when they turn up. Like if a single magic weapon showed up in an ACOTAR campaign, that would become what the campaign was about.
Edit: I feel I should add, that Frieren: Beyond Journeys End has a D&D vibe.







