I've mained WW for all of Legion, and I've preferred Serenity to SEF for most of that time. Prior to 7.1.5 I found it to be the most interesting cooldown available in the game, and one that gave WW monks a very high and IMO extremely entertaining skillcap. That was because of how it interacted with our hard-hitting cooldowns: RSK, FOF, and SotWL. Because, at the time, the cooldown reduction aspect of Serenity lasted after it's use, there were a lot of possible ways of getting optimal usage out of it, for example using it while some (maybe even all) of RSK/FOF/SotWL were on cooldown, and having them get off the cooldown within the Serenity window, and in turn have a halved cooldown when Serenity was over. So there was an interesting trade-off between getting as many uses of your skills through Serenity as possible, versus making sure you got all of your abilities into the Gale Burst window, while not delaying abilities or Serenity itself as much as possible.

Prior to Nighthold I wasn't really raiding in a serious mythic guild and concentrating on getting high parses, so maybe someone can correct me, but it truly felt like Serenity at the time gave us an interesting, dynamic playstyle that was very hard to completely optimize.

However, for whatever reason Blizzard nerfed this in 7.1.5 with the patch notes: "Fixed an issue with Serenity that caused its cooldown reduction to extend to in-progress cooldowns beyond the duration of Serenity." I wasn't really active in MoP/WoD so I don't know if this 'excuse' that it was an unintended 'issue' is valid, or if it got nerfed because it was a too complicated ability for their targeted audience today. I seem to recall some excuse in a blue post about it being a change to how haste affecting abilities affect cooldowns, but that seems very strange since Serenity has nothing to do with haste.

In any case, after this I've felt Serenity has become a really boring cooldown, that only makes sense when it's propped up by set bonuses and/or legendaries. In NH it sorta worked out because we were running with the legendary wrist and chest combination, and it was kinda a bit of fun being able to get really long extended Serenity windows that felt a bit meaningful because spamming BOK/SCK, while it did pretty mediocre dmg, gave us a lot of stacks to use CJL often.

TOS was more of the same, only now we had the icky gameplay of cancelling FOF inside Serenity. Still, with the legendary wrist it kinda worked: extended Serenity meant getting lots of buffed RSKs off.

Now in Antorus SEF is obviously miles ahead of Serenity, but still, have anyone been playing with Serenity without the legendary wrist and actually enjoyed it? The window feels short and without much impact: what distinguishes it from SEF is pretty much that you get an extra RSK off inside of Gale Burst.

I've been playing a bit of beta (mostly leveling, no raid testing yet), and from what I can tell it's possibly even worse there than on live. Even without T21 and the nerfed Energizing Elixir, we still have all the energy/chi we need, and to boot we've lost SotWL so that's another ability you can't use within the window.

I can imagine that certain Azerite traits might 'prop up' Serenity again and make it the go-to for certain tiers in BfA, but abilities shouldn't feel like garbage by default.

The fundamental issue with Serenity now, it seems to me, is that that the 'free Chi Spenders' aspect isn't all that relevant to the current WW monk because BOK and SCK (outside of AoE) aren't worth much to spam, and now that the cooldown reduction aspect is reset after Serenity (the 7.1.5 change) AND we can't extend the window with the wrist legendary, the only 'benefit' that cooldown reduction gives us is that you get an extra RSK.

I'd be happy to see any other opinions regarding this. I feel like people everywhere are praising WW monks, but personally I feel the spec has really diminished since 7.1.5 thanks to this change. Is there anyone who likes the new Serenity?