All of what you described above is not in place because of pro gamers though.
Catalyst does not open sooner for raids to have some relevance in the first few weeks of the expansion. I may not agree with this decision, but it is what it is.
Valor is capped for the reason to prevent too much of an itemlevel gap to form between those who have a lot of time to play, and those who have little time to play. It helps contain the itemlevel gaps between the two groups, so the game does not turn into “spend 20 hours a day doing M+ or you fall miles behind” rushfest.
Personal loot was mainly taken away because it dis-incentivises social interractions and communication in raids, and propagates the thought that the loot that drops is “your’s”, which it isn’t.
Most content does not release overtuned, and the ones who do stay like so because Blizzard expects the power inflation from itemlevels to help those that struggle to overcome specific bosses with brute-force methods. When that does not help is when they start massive nerfing content (like how they just massive nerfed Razsageth) which was something they kept doing on a pattern that is pretty predictable.
Meta shake-ups do not happen because of the way gearing works. If someone already invested their time in building a character only for it to get nerfed halfway through the tier is going to do more harm than good. And no, the meta is enforced by the community, and up until the breaking point (which is 20s right now) is not needed. Classes are pretty close to each other currently, with only a few outliers having issues in specific departments.
In every type of game it is normal that you balance a class based on what professional players can do with them, as they are the ones who can push a spec’s capabilities to the limits, and see what balancing issues a spec may have. What Blizzard is failing to do is to make classes easy to pick up, which these days is important because people do not bother/want to/can’t get the basics out of their specs. For cases like these it helps if the class is easy to get into as it leaves less players frustrated.
Feral was a perfect example of this from Legion, where Blizzard went out of their way to rework how their bleed snapshotting works, making the spec much easier to play (while also nerfing it slightly as a result). This nerf was only really noticeable for those who were playing the spec at a very high level however.
Difficulty does not mean the same for everyone, keep that in mind. A lot of people here complained about Razsageth being much harder than Jailer, but being one who progressed on both of them on heroic level I can say with certainty that Jailer, pre-nerf, was much, much harder than Razsageth was pre-nerf. The Jailer had less strict DPS requirements, but harder mechanics that had to be respected, while Razsageth’s mechanics are more forgiving, but in exchange the HPS and DPS requirements are tighter.
Regardless, people will always scream that something is overtuned if they cannot just roll over it, which they could do with every other previous boss in the tier, with the exception of Diurna and maybe Dathea.
