I think the problem was caused by trying to force it into gatewatch-era magic canon. Look at Lorwyn for example: they had pie-thieves, goatnappers, and fairies, so not every story is going to fit there, but they could tell a fairy tale. In gatewatch-era magic stories, however, you aren't allowed to tell that kind of story. The gatewatch are audience surrogates, so every story about them has to be written in a certain way to preserve this audience surrogacy.
In order to do so, every gatewatch story must fulfill these criteria:
1: The characters must do what the audience themselves would do. If the character does something that someone in the audience wouldn't themselves do, then they might not relate to the character anymore, and that would be bad. Which feeds into
2: The characters always have to be unquestionably, perfectly, morally right. If you put a difficult moral issue in, some of your audience will choose one side, and some of the audience will choose the other side. Regardless, half your audience will end up disagreeing with your character, and won't be able to relate to them anymore. And in order to maintain this, it's necessary that
3: All antagonists are plain, simple, wrong: If the antagonists are right about anything, then the protagonists aren't always right, and that's not allowed. There are some audience surrogate stories where the protagonists show the antagonists the error of their ways, and everything is resolved peacefully. But this is mtg and these are planeswalkers, characters whose distinguishing feature is their magical capacity for violence. When all you have is a
hammer, every problem looks like a nail. Which means that
4: Every antagonist must be pure evil that can justifiably be dealt with, and can only justifiably be dealt with, by killing it: Let's look at the start of the gatewatch hitlist: eldrazi, then more eldrazi. They're very obviously a bad thing, that any sane person would be opposed to, and really the only way to deal with them is to kill them. There's no question of whether they should be siding with Zendikar or the eldrazi, there's no bringing them to the negotiating table, and no complex ethical question about whether to kill them or bring them in to face a fair trial by a jury of their peers because killing them would make you the REAL monster.
The Kaladesh setting was fine. The Kaladesh antagonist was also fine: a conservative regime that restricts creative freedom out of misguided dogmatism, and it actually fit very well with the upbeat steampunk setting they were trying to create; a lighthearted antagonist for a lighthearted setting. But this is a gatewatch story, so the antagonist can't be that. They have to be evil, and they have to be killed. They have to be human eldrazi. And they weren't.
So, how could they have written a better Kaladesh story?
The most obvious way is to not make it a gatewatch vs eldrazi story. Take out the dead daddy, and make it a civil conflict between ideologies about artistic freedom vs dogmatism, a "footloose" adaptation. The problem with this is that magic is a battle-themed game, so it's hard to make cards for a story that isn't resolved with violence.
Another way would be to make the antagonist an eldrazi-style non-human force that's oppressing creative freedom. Maybe a giant legendary gremlin that's eating all the aether and shutting down the plane's creativity. Maybe make it a natural disaster, like time spiral block, that the planeswalkers need to fight. But it might be hard to tell a good story without a human antagonist.
Or, make the antagonist something that's actually evil, instead of a government that doesn't sponsor free expression. You can even keep the artistic freedom and self-expression element by making them an allegory for the government's more tangible forms of oppression. Do a real steampunk dystopia. Of course, you'd have to ditch the happy, optimistic
aetherpunk environment.
So there you have it: you do happy, optimistic setting, you can do human antagonist, or you can do justified use of force. In fact, you can do any 2 of them. But you can't do all 3.