There's lots of reasons to not like what the designers do in WoW. There's a lot of reasons to think that their decisions don't match with your playstyle, and there's been plenty of times where the direction of the game curves such that you wonder if you're still going to want to play it. There are even times where it's a good idea to step away for a bit and hit up another title. And yes, it's okay if you decide not to play, too.
But, and this is a big but, it's not okay to flip a table over anything -- especially a small nerf. Ghostcrawler tweeted yesterday:
Dear world, if you react hyperbolically to even modest (3-5%) nerfs, then it makes it hard for us to tell when you are really concerned.- Greg Street (@Ghostcrawler) September 26, 2013
No matter what you think of his and his team's decisions about the direction of the game, it's critical to approach them with a level head and perspective. A 4% nerf is not going to cause you to stop having fun, and a small buff is nice, but it's realistically going to have little to no impact on your gameplay. It's not going to stop you from standing in fire; and for the vast majority of us skills like that are much more important to DPS than any buff or nerf could ever be.