Updated review from launch to Cataclysm.
The game is no longer a grind, the quests are more interesting and flows much better. Your map will now indicate where to go to complete quests and where to turn them in. The dungeon finder (I believe this has been around for awhile now) was a brilliant idea, as you no longer have to spend an hour finding a group and then traveling to the dungeon to do it. You just pick a dungeon and they find a group for you cross realm. I was in a group and playing a dungeon in less than a minute.
In its current state, I would say the game is almost perfect. The game feels like World of Warcraft 1.5 since it has improved so much over the years. The only negative, is that the earlier zones are not very populated anymore, even though cataclysm was an effort to bring everyone back to the earlier zones. Most people are already at higher levels since they have been playing the game for years and quicker levelling will get you through these earlier zones much quicker.