Because there can be multiple reasons, and more than one of those might be worth discussing? The main issue with TF is forcing players back into content they've outgrown, shit players getting better gear than they deserve is secondary to that, but still relevant. Also, gear and skill are not mutually exclusive, you can have both(and if you're good, chances are you'll do your very best to get gear/AP etc)
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"Most of Blizzard's other games?" HotS esports never took off in the first place(it's being artificially propped up by Blizzard, that's it). SC2 died very quickly and is now in the same situation as HotS essentially. HS has never been taken seriously as an esport because of how random it is and keeps going further in that direction. WoW arena is very niche, and considered very poorly balanced generally. That leaves OW as the only game with any real esports success.
Don't necessarily disagree with your first point, though. The world first race is probably not getting a lot of people into the game, because most of the people who care also raid or raided anyway.
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Yeah, no real player depends on gear, that's why all the world first guilds go into every raid entirely naked and just skill the bosses to death. Are you actually serious?
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By using one of the suggestions that have absolutely no impact on you(making mythic drops the maximum ilevel when they drop, or capping other stuff at mythic base but letting mythic forge a couple of ilevels higher). Again, you can have your craaaazy random loot, but that can be done while also allowing mythic raid loot and mythic raiders to not have to be part of that RNG fiesta.