TL;DR: The balance team is struggling (mainly because of low-skill vs. high-skill differences, and Play-offs/Worlds is coming soon), not trolling.
Several of the changes are aimed at pro-play. And most of them make some sense.
The buff to Yasuo's ult is decent because ult-related changes tend to be more impactful in pro play (because people don't fight as much without their ults). Although, of course, Yasuo is already busted below Plat, so they can't go through with any straight buffs. And would you look at that, it was reverted on the PBE. Edit: I just noticed Yasuo also lost a bunch of power from the 8.15 changes. He's actually a tiny bit weak overall. Those buffs will probably come back at some point...
The orianna nerf is because Riot doesn't want Orianna to be the #1 "safe" mid-laner for the millionth time in Worlds.
And the buff to Lee Sin was definitely overkill. I'm fine with complaining about that one. They reverted it already, though.
The Hecarim buff is just a compensation for the Celerity nerf (not related to Worlds this time). I am 100% certain about that. And it's focused on his sustain damage, rather than his burst, which I think is appropriate.
Zoe nerfs are necessary of course. They can't go any further than they did, because they don't want to make drastic (mechanics-level) changes before Worlds. And they probably don't want to change her mechanics anyways, because they're unique and interesting ("fun" is up for debate). Whatever, she'll be in the same spot as Azir pretty soon. It's a tough situation. There is no winning situation anymore. Maybe if she wasn't released with so much bullshit, it would be easier to cut some of it down without "destroying her playstyle/identity".
So yeah, there's some bad decisions in there that are already reverted, and Zoe is a problem without a "good" decision available. But most of the changes make sense in some way, if you think about it. So I wouldn't say the balance team is trolling, just that they're struggling.
Maybe one of these days they'll get over their "same game, same rule" policy, and make a pro-specific version of the game.