I dunno if it's been linked here, but Alex Brazie (yes, the same one who got fired a couple weeks ago) did a blog post relevant to this discussion.
Those who make the claim that WoW was a better game back in the day would do good to read it. To summarize, the game comes off as worse now because the stimuli that initially hooked you into the game aren't as effective anymore. When you started and everything was fresh, you wanted to hit that next level, you went gaga over a new piece of gear or spell, and felt accomplished when you downed a troublesome boss. If you ever completed a legendary, it was a magical feeling, like you were on top of the world.
But eventually, the feelings you get after each shiny thing start to dwindle. When a boss went on farm, it was less like defeating an old nemesis, more like stabbing it in the gut and walking out with some more loot. In an attempt to shift the blame on these feelings from the player to something else, it's easy for them to blame Blizzard for changing the game and making it unappealing to them, when in actuality nothing that Blizzard does will remove their ennui. They've run their course, and it's time for them to move on.
That's why, no matter when you start playing, the game was at its best then...according to you. Sure, those that started in Classic or BC mock those who claim that Wrath was the best expansion, but that's only because the former started earlier and were deep in ennui's throes by the time the latter started playing. Down the line, there WILL be players who claim that they had the most fun in Cata.
Now, I'm not saying you should agree with every decision Blizzard makes. Far from it, criticism helps the devs understand problems or concerns. But at the same time, you should question whether your dissatisfaction with WoW is specifically due to a particular decision, or if you're just worn out. I started in Wrath, and back then, I gladly spent countless hours questing, dungeon grinding, raiding, and more, because everything was so fresh and new to me. Cata began to wear me down, and while part of that was due to a feel of a lack of content, and another part was my personal situation involving a crumbling guild trying to hold itself together, a third part was just the fact that I was getting tired of the game. It just wasn't as magical as it had once been. Today, I don't play as often as I used to because I don't want to get burnt out so quickly. The game is just fine nowadays and (I believe) is better off development-wise than it was in Cata.
In short, if you played back in the beginning, you're just not going to get those feelings you did when you started, no matter what. Find something else to play. It's okay to let go.