I would have to disagree with the game being less fun or less enjoyable nowadays. Like many people here, I was around during the 7 hour Molten Core nights and knocking down Onyxia, and they were fun and memorable. Nothing was cooler than knocking down that big stupid pink dragon for the first time, or opening the cache of the fire lord. But I also remember the hour-long afk's, the fights over loot, the cancelled raids because not enough people showed up. And I also remember vividly the disbanding of our guild just before BC - another casualty of inevitable drama.
BC, for me, was a beautiful time. Our fresh new guild made up of 15 from pre-BC was poised to take on the world, and we did. We hammered up to 70, and then the first wall: The runing of Steamvaults and Botanica and Shattered Halls ad infinitum until we had enough of us revered enough to run the heroics. We pushed through, and got eventually started Kara, where we hit the second wall: The difficulty of Kara at the beginning. Granted, most of us were undergeared and hadn't run enough heroics - but can you blame us? We were so burned out from the regular runs that we wanted to experience something new. It wasn't long after that that four or five of us burned out and quit playing.
When I picked it up again, I started a new toon on a new server with a friend who had just started. For him, everything was new and exciting, and he was moving along much faster than me. Thankfully, 2.3 came out right around that time, and the leveling process became bearable in the old world. We eventually made it up to 70, and found a small group of like-minded people, and started burning through Kara. And then we hit the third wall: the jump from 10 to 25 man raids. Our small group of friends who had worked to get through Kara started recruiting so we could start in on Gruul. It wasn't long before the guild collapsed under the weight of new recruits and old grudges, and we were forced to go our own way. By that time, I had every piece of badge gear and Kara gear, and was itching for something new. I pugged into the occasional Gruul's lair, but The Eye and Serpentshrine were painful to pug through. Eventually I landed in a larger guild that I could get semi-regular runs with and started slowly working on SSC, with Gruul and Mags always on the books. But that guild was sterile, and it wasn't all that enjoyable to be a part of... I was looking for a real challenge, so I found some of the top tier guilds, and joined up with them. But it was the same thing... people were grouped together out of necessity, not because they enjoyed the company. You could cut the tension on vent with a knife.
At the end of BC, we were working on BT, but not getting that far, but every raid night, I was there, flasked and farmed and ready to go. But I wasn't having fun. So I gquit and spent the next little while wandering alone.
When Wrath was finally launched, I joined up with a friendly, if not noobish guild. Now, Scarcely two and a half months after launch, a small group of us have begun clearing end game raids, and just last night, we downed Kel'Thuzad, and the event was as memorable as anything I've experienced in game.
With just 600 health left on the boss, our MT went down in a pile of scrap metal and holy light, our healers were dead, our dps were dead. It was over. We had come so close, so quickly. To fail now was heart breaking. But wait, in the shadows, a vanished rogue was chasing down the boss, with scarcely a hundred hit points to his name he snuck up behind big ugly and with a quick stab of his dagger, the night was ours. We celebrated and cheered and hooted and hollered and congratulated each other and retold the story to each other from our own perspectives, each of us crumpled on the floor.
Even last night, after the glow of the final encounter was over, we reminisced about the old days and how easy the new content is. I'll admit, the new content may be easier, but because it's more accessible makes it that much more rewarding. I never got to see Illidan, but now, with nine friends, I'll be able to stare down Arthas, and reminisce about that fight when we're looking down the ancient crypt that keeps Sargeras.