Okay. Emerald Dreamcatcher.
https://us.battle.net/forums/en/wow/...page=3#post-57
Of course, they changed it a little more next patch due to power differences, but I'm pretty sure this is the example you wanted me to post.
Blizzard: "We're nerfing EDC because it's too strong."
Players: "We're okay with nerfs, but don't kill the weaving gameplay"
Blizzard: "Why?"
Players: "Because Moonkin, honestly, is pretty easy, and this playstyle is very hard to master. It's fun for us."
Blizzard: "The difference between good players and not-0so-good players is too high with this item."
Players: "Okay, but we still enjoy the playstyle -- we just don't want to dump Starsurges mindlessly."
Blizzard: "Balance Druid lacks variety, you guys aren't wrong. How about this change instead?"
Players: "Yeah, that's pretty good, sims are favorable for your tuning changes too."
Blizzard: "Awesome, thanks for the feedback."
-------- Then the patch dropped and retuned the effect from 7 AP/ 3sec to 5 AP / 5sec -------
Blizzard: "We still aren't happy with the power differences from good and not-so-good players."
Players: "It's not a nerf unless you're top5 world, so no biggy."
Other Players: "bliz sux, dumb nerf"
Players: "It's probably a buff for you."
And now we don't care about this change because OI is more favorable for movement, obviously, then EDC.
- - - Updated - - -
Once they go into code lock, it's pretty much the finished product (now going into the polishing phase). Mechanics are typically expansion-level changes unless there is a big issue that can't be easily resolved. (Tuning is easy. New code is rarely the answer.)
So, in a sense, it does get saved for later.