Good question and the subject that has come up recently way too often. I agree with most of what people say here, th game has been stripped of most fundamental aspects what made it so attractive and satisfying to play.
And it begin in WotLK, when Blizzard introduced all beloved (NO) Looking for raid and looking for group. Hell, even doing quests was a challenge back then, with no indication on map where the quest actually is, using Websites and reading descriptions of quest. I know someone will be happy to drop "but that time wasting and boring", but guess what that was how player interacted with world around you. Exploring, getting into sticky situations in areas, ganked by opposite faction, but when you got your quest delivered that loot felt deserved, actually making difference in your playstyle, not just another # ilvl just to be replaced in next 15 minutes.
Dungeons were not only hard to go through but to find a group was challenging where in every dungeon certain classes shined. Raids and even Dungeons made you stand out from the pack. Because of that, communities were forming, guilds where people bonded and were valued for their skill not their item level. It was an prestige content which was hard and not all the players would be as good as others and thats how it should be. Just because you are paying for subscription doesnt mean that all its content should be allowed from the get go, there is a grind and pruning of skills to each that end content. The gratification and satisfaction comes from that, not everything being chewed up to f*cking nothingness, where your item level defines how viable you are to enter the raid, pressing 4 keys on your keyboard, considering how much pruning has been done to classes.
Player has no more control in planning in gearing, RNG has consumed this game in order to create this void before you are able to decimate the boss fights. Its unfair to playerbase, as progression is based on your luck! I dont want someone to get better recognition then anyone else, including myself, because their RNG was better then mine. Even gear has became so generic, no more difference between Healer/Tank or DPS armor pieces. As a Damage Dealer it was important for me not to miss my Damage on the target.
Races have lost all their identity, those small racial skills made each one stand out for their class. Some race had better classes then others and that made it more engaging, rather then picking character for looks. It felt like all the races had some value, unlike Zandalari trolls being shoved down our throats with their ridiculously overpowered racials.
Story has been dead after all the WC3 content was exhausted. The player is so detached from the world that he/she only follows the current events while all the other existing races or factions go in afk mode do nothing, which causes massive inconsistencies in their storytelling and identity of character or the race in whole.
In short Blizzard has turned all time loved game of adventurers life into RNG based marketing nonsense, where everything is so chewed up and delivered to you on silver platter that it provides no actual satisfaction and love for game. Game of Casuals! Make the players adept to the game not the other way around. Because it results in low standards of the game! When your playerbase has no desire to invest their time in game and will quit first thing something goes south for them. But Blizzard has done absolutely everything the "fans" asked for just to fail again. Mob will have endless desires, but that wont save the game. Taking a system that works, starting it over with new ideas just to fail miserably wont save the game.