Do you understand that systems can only change so much in an alpha, due to the length of time it takes to consider, make, and re-test major changes?
As example, they couldn't have fundamentally re-worked or removed Azerite, even if in Alpha all responses to it were "This is the shit-est thing ever!!!" (which they weren't, either, contrary to revisionism - but it wasn't very positive either). They can change numbers. They can add or remove specific individual powers/abilities/items. They can makes fairly big changes to how things are acquired, but basic stuff like "You have three items which have Azerite powers and you need to gather Azerite to make a number increase to make them go", that's not likely to be possible to change within the framework of alpha/beta.
Alpha is mostly about testing a buggy and unstable version of the game, which isn't feature-complete, but where all the features are already in the pipeline and due to be added fairly soon (and will be before Alpha finishes).
What you seem to think that an Alpha is experimental thing where they can just try stuff out, where they can implement entire systems and then later pull them and so on, because people didn't like them, but it isn't. It's just beta with way more bugs and not all the features in. Again, for total clarity, the features aren't in the Alpha aren't "subject to change" in a huge way, they're just not even testable yet. Once a feature is in the Alpha, it is very, very, very unlikely it's going to go away entirely, even if people don't like it. The numbers might change. A specific ability or whatever might be removed or totally reworked. But if, say, Covenants come into the Alpha, and you don't like the basic implementation of them, well, that's not going to change before they go live.
As an example of how long this takes, Essences were probably conceived in response to the poor reception that Azerite abilities got - particularly as a very, very common EARLY complaint re: Azerite was "all these abilities are passives". They probably started work on them in BfA Beta, maybe even Alpha. But no matter how mad people were about Azerite, Essences couldn't have appeared in 8.0 or Beta.
TLDR: It's not useful to think of Alpha as a period where "anything can change", whereas Beta is "Just numbers and bugs". Alpha is just an incomplete Beta. The main reason things are subject to more change in Alpha is that it's further from release, not that it's a fundamentally different period. It's not, note "Early Access". They're not going to completely re-work major systems they introduce just because you don't like them.
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I feel like you should have that painted on the wall in your house/flat hipster-style, in a cheery font