This is your problem. You decided you knew what the Devs intent was an wont listen to anyone, including the Devs when they tell you something different.
So, when do you think they develop an expansion? Do you think they story board, fine tune, code, test, and then release an expansion in the last 3 months of a previous one?
In truth they are already working on the next expansion when they release one. They we already developing BC during Vanilla. They were working on WotLK during BC, etc., etc.
They had to know about Zovaal before BfA because they had to already have it story boarded out.
And how long do you think those high quality cinematics took to develop? You think they made those a month or two before release? To get Saurfangâs story in that form would have meant they were already working on them before BfA was released. And their culmination was VERY tied to Sylvanas deal with Zoval.
They did, you just missed them. Here is one for you. Do you remember the fight between Sylvanas and Malfurion? They called out that she should not have been able to stand against him. They called out that she shouldnât be that strong. They were already hinting that she had gotten some kind of power boost from somewhere.
Not really sure how you missed that one. It was actually a major talking point on this forum at the time. Everyone asking how she was that strong.
First patch: âHey guys, look Sylvanas is way stronger than the used to be.â
It wasnât subtle. We didnât know what the reason behind it. They didnât hang a Zovaal sign on her. But, Sylvanas made a deal with someone/something was pretty explicitly laid out.
You are reading a cause in that is not supported by facts. Development time does not allow improvisation like you are describing. They knew where they were going, what they aimed at. Shadowlands was already well into development when BfA was released.
The story was bad. But it wasnât bad because of improve. It was just a bad story.