You have got your facts backwards.
ANY balance change is ultimately done to appease the player base. Thus ALL nerfs you found were done to appease the (not necessarily angry) player base.
Though you do raise the key issue namely
Arguably, the experience for as many players as possible. How do you do that? Observing balance as a better measurable criteria in the fact of not being able to directly measure player experience reliably. It is not that they do balance changes because balance in itself is good.
They do it because they cannot directly estimate player experience usually. Blizzard would disagree with “playing experience first”? That’s such a garbage statement. Imagine a dev coming out here and saying: “Playing experience is not our first priority.” People play games mostly because they like the experience, not because it is balanced. Then they would play tic tac toe.
There is also the misconception that any problem is easily solvable. Let’s take your Big Priest example:
- Do they even know if many people see Big Priest as a problem? Probably yes. But are there that many as it seems on forums?
- As you said other people playing Big Priest would likely not be as active in communicating. So maybe there are more people who like it than dislike it?
- Does deleting Big Priest improve player experience? People are usually good at pointing out issues, but usually solving them is not as simple as it may seem.
- I do think they should do something about it, but maybe they know more, or maybe they just work suboptimally in some cases?
If you are not convinced: Tell me why balance is good. Very curious here
Edit:
Also found an example here. Although it is not an example for a nerf you asked for but I guess that counts too