Meh, not gonna complain about W10 much. As long as it runs the game 
In any case, at this point I basically **had *to get a new computer. My 2008 iMac has not been able to run the last two versions of MacOS X, and it’s too old to use Apple’s new graphics API, “Metal”. So I’ve been stuck with the last version of OpenGL that Apple implemented, and Blizzard finally announced that, after several years of applying duct tape to keep the game working with OpenGL (including some things that made the game look like shit, but at least be playable), they are abandoning OpenGL support as of Battle for Azeroth.
*Heh - as soon as I get time, I’m going to find good places in-game to take screenshots. I’mma take a screenshot on my iMac, with all of the graphics settings where I have had to keep them to play in Legion, and then leave the character exactly where it is. Then I’ll log in on my PC and take exactly the same screen shot. I’ll share them somewhere, side-by-side to show the difference.
Right now, I am mostly boggling at how water looks and acts at settings higher than “Low”. Aside from water, I’m am being amazed at seeing things in the game that I had no idea existed because my graphics settings never let me see them.
I’ve also installed Diablo 3, which I purchased at launch and then played for about two weeks. At launch, my iMac already couldn’t really handle it, and with the graphics turned down and my resolution reduced, it looked like complete shit. Then I installed Heroes of the Storm, which I had installed on my Mac and then discovered it was unplayable (mostly because it would just lock up at the beginning of the tutorial).
Also installed SW:TOR and rolled a character, then played just far enough to be offered my first quest. Haven’t gotten back to it - too much to do in WoW still.
There are some serious tuning issues in the open world as well. I’ve got a bunch of level 70 characters who are in the process of Loremastering Outland. Before 7.3.5, they all completed HFP and Zangarmarsh, and two of them had completed Terokkar Forest. Now another is starting Terokkar, post 7.3.5, and holy crap is it a lot harder, but not so hard as to be impossible (and of course, the first two went through there at level 70, but fighting lower-level mobs; the current toon is fighting scaled-up mobs).
But my monk in Draenor … um. In the final Shadowmoon scenario (the Defense of Karabor thing), remember Karnak the Burner or whatever - the orc with the flamethrower. He was always challenging, but now he is basically one-shotting my monk. I gave up after about six tries. And then in Gorgrond, there’s Khaano, the guy whose brain gets scrambled in the red mushroom area. Cannot beat him. He was never a problem before.