You're missing the forest for the trees. Every expansion reuses existing assets, rigs, etc. Yes, they reuse tree models... But every single thing in this, including the major set pieces seems to be reused or modified assets.
No expansion has ever reused assets this heavily and in such a dense concentration.
Sure. They throw old trees in now and then. They also make new trees for basically every zone, because foliage is a big part of making zones feel new, so when you make a canyon-y, rocky red zone similar to Waking Shores, you don't put in Waking Shores trees, because that makes it feel like just Waking Shores. You throw in new, visually striking trees so that it feels like a similar but new zone.
It's very likely that living world assets (the birds and butterflies) will show up in 11.0 zones. It's likely that some of them will be reused. But what are the chances that you take four random screenshots from a trailer or press kit and two of them
just so happen to have slightly modified existing living world assets in the exact same front left, easy to see position?
Sure. They reuse or upscale assets. But what are the chances Blizzard sits down to make two huge set pieces in a zone, like giant highly visible statues carved out of a mountain, and they make one an upscaled existing asset, and the other just a dwarf player model in an existing animation? Imagine getting a first look at Vol'dun, and the pyramid was just higher poly vanilla ZF pyramid and in the background, instead of a new, striking, visually distinct snake statue, they just had a
stone colored old cobra model.
What are the chances you take four screenshots of different zones (or areas), and of the almost dozen creature, critter, etc. models in the screenshots, none are actually properly new, just mashed together existing assets?
And you have basically no new aesthetics?
And the screenshots "just so happen" to conveniently have a reference to recent official twitter pictures?
And the same extremely basic skybox when the art team has been going 150% on skyboxes lately?
Individually none of these are a huge problem, but together? Go rewatch the dragonflight/shadowlands/etc trailers and see how immediately distinct the zones are. The chances of the art team suddenly phoning it in after 20 years isn't 0, but it's really, really low.