I can see a number of points that I believe have contributed to the sad state of the game at the moment, some of which have already been mentioned.

I've played consistently since halfway through Vanilla WoW and can say without doubt that the most fun I've had in the game was during TBC. Some of the things that have changed since this time that are negatively affecting my experience of the game and, in my opinion, other people's experience, are:

1. LFD. The LFD tool has hurt the server community. People don't know, nor have a reason to get to know, the other players on their servers as much as they used to. Previously, each server had to work with its own population of players in order to form groups and accomplish dungeon runs. This contributed greatly to the sense of being part of the WoW community on our servers. If the LFD tool worked within servers, rather than across servers, I think this would be a better mechanism from a server community point of view. Keep in mind, it was the early WoW community that contributed this game becoming awesome.

2. This is closely related to the point above... instant ports to dungeons are kinda convenient, but they definitely take away from the number of world encounters that we may potentially get involved in. As an example, travelling to dungeon entrances opened up opportunities for pvp - remember all the fun/frustration (strangely, frustration can lead to both fun and a sense of accomplishment) of pwning members (or being pwned lol) of the opposite faction around the summoning stones, or the random events that occurred whilst travelling to and from the dungeons? This is a fantasy mmo afterall. Travel and exploration are essential componenst that worked just fine during the early iterations of this game. Taking them out to appease the lazy is resulting in everyone becoming lazy and contributing to us all not having enough to do.

3. Flying Mounts. This has been commented on somewhere else here and also relates to point 2. above, but flying absolutely everywhere also reduces the chances of random interactions with the world, its environment, and other players.

4. Attunements. Yes, sooo many people have complained about not liking doing attunements. To the point that the game no longer has them. Strangely, now everyone is complaining about not having anything to do at endgame!? Attunements were awesome, whether you realised it or not. They expanded the lore of the endgame world, provided challenges and goals to be achieved, and they provided a considerable amount of content for players to work through. Now that they are gone, we have no real goals to work towards, apart from downing random bosses for no apparent reason other than loot. Which brings me to my next point...

5. Raid Quests. Where are they? Why am I going into these raids in Cataclysm? I'm sure somewhere during my levelling quests something pointed me to them, but now that I'm here I can't remember what it was and my reason for entering these dangerous dungeons eludes me. What made Karazhan the most loved raid instance of all time in WoW? The whole instance told an epic story. Everything from the attunement quests, through to the design of the instance, and especially the quests that were gradually achieved as we completed our way through the raid. All of which contributed to rep gain and awesome quest rewards - it was worth doing and felt rewarding! Cata has none of this.

6. PvP!? Rated battlegrounds are a failed idea. Back in Vanilla and TBC a much larger proportion of the player population PvPed. Why? Because it was worth doing. The gear rewards were simply awesome, and everyone could have access to them if they contributed time to that aspect of the game. As a result, people played.. a lot! PvP (BGs) was fun because everyone was involved, the elites and the noobs. More than this, it provided a tangible goal for people to work towards, which gave them a reason to log in and play even if it wasn't a raid night.

7. It's not the difficulty. The difficulty of the game isn't the issue. Challenge is a good thing in a game, especially a fantasy mmo that encourages strategy and team work. It's the little things mentioned above that have drastically, and perhaps subconsciously, changed how we feel about being within the world of Azeroth. The game has previously been much harder than it was in Wrath and is now, yet it was still the most popular game of its kind in the world... something to think about perhaps...

I'll conclude by pointing out that for all of the people who I have played with since the Vanilla days, we all share the sentimentality that the game was at its best in both vanilla and especially TBC. What's the one major thing that has changed between Vanilla-TBC, and Wrath-Cata?... the blizzard development team. The orginal team were the A team, hence their removal from WoW for the purpose of developing its successor, "Titan".

As much as many faboys out their love their Ghostcrawler, I personally believe the new development team have concentrated too much on appeasing an audience who aren't intelligent/aware enough to know what they really want, rather than continueing to make a game awesome because of its community, its challenge and the rewards gained.