I'm not sure I see the issue? The system change, among other things, slowed down the rate at which we plowed through new arts to the point where it should be obvious even to people only following RR or the book releases that something about how Ling Qi learned arts has changed. The in-universe justification for the shift is that just as Foundation is the point where your domain is advanced enough to integrate part of it with your domain weapon, Threshold is the point where it's advanced enough to study arts at a deeper and more philosophical level.
In the old system, we needed to have complete mastery over an art before we could begin tweaking with it, but under the new system, we study the philosophical basis of the art directly by default. Since we're already poking at the foundations of the arts as we learn them in the new system, why shouldn't it be possible to tweak them as we're going along? Especially when we've already practiced art modification? Or if we really wanted to make sure we have in-universe justifications for our more aggressive art modifications, we could wait until after FSS+ to proceed with them - I believe FSS+ is planned for Soon™.
If it were just WHR under consideration I wouldn't really care what justification we used, but I've been under the impression that several of our arts (e.g. SNR) were regarded as similarly awkward, and opening up live art modifications as a perk of Threshold (or maybe Framing, if Threshold seems too soon) could allow us to work around those problems while reducing the need to introduce yet more entirely new replacements into the narrative.
The way that the shifting framework for Ling Qi's interaction with arts was described, these kind of deep tweaks should be
harder on an unmastered art, not easier. She's operating on what's described as an objectively more challenging level.
I readily accept that it's now more plausible for her to make major changes like substituting an element(fire->dream) and the skillset it's based on(music->formations), because she's now able to operate on the conceptual level of the art's construction. I also accept that Ling Qi should have a bit more flexible in tweaking arts as she masters them, tailoring them to herself in little ways.
However, neither of these changes justifies being able to make major structural edits to an art that she does not understand. And that's the whole point of lacking mastery- Ling Qi fundamentally doesn't understand the art's complexities, or else there wouldn't be any projects in it to learn.
But it's not even a close thing, with not just one but
three projects, excluding Garden of Mists, remaining in WHR. And to a degree that's actually exactly what makes Garden of Mists so tempting in the first place! People want to be exploring the themes hinted at in this art, they just want a more fitting context for the exploration, which Garden of Mists provides. But the very fact that that exploration is pending, is an object of yearning, proves that Ling Qi doesn't reasonably have the grounding in the art
or the concepts to be making the mass adjustments asked of her in the Garden of Mists project. The entire thing is such a valued magnet of our attention
because she lacks cohesive grasp of the material.
The reason I'd like circumstances to shift to be a bit more realistic with the in-setting mechanics is that it'd avoid undermining the journey by requiring so much of Ling Qi at its start point. It would be very limiting, in a narrative progression sense, to have Ling Qi simply muscle out the edit on her own in an extraordinary display, since that puts sharp limits on her starting comprehension, by necessity. As in, it pins it to a very high level from the outset, which naturally restricts how much wiggle room you have. There's a genuine question of where she moves forwards from there, and in the worst case it ends up simply eliding most of the thematic exploration people were looking for in the first place.
tl;dr: People want the learning experience from WHR's themes. Major manipulation of arts at Ling Qi's level of cultivation definitionally requires "having the answers". These are in innate contradiction to one another; Ling Qi hashing out the art edit on her own requires that she has less to learn from the art than otherwise, and all but guarantees that narrative experience, which people don't want.
Edit: and in any case, tossing out awkward stuff entirely is
fine. As much as we don't have the time or space to add new things, we even more don't have the time or space to spend on hammering arts into shape that just don't move in the direction we want to take things. Because that takes a lot more narrative time and space to do. SNR's 100% on my chopping block and will yeet it at the first opportunity, for example.