Upon hitting 85 on my main, I looked around and realized that I had no motivation to do what I’d already done several times before in previous expansions. One month later and Tawyn’s still in greens and I’ve hardly touched her. I did have a brief spurt of motivation when I remembered how much I absolutely LOVED doing Uldum, so I ran over to my Horde-side hunter, powerleveled her to 83 specifically to do Uldum, and went and did Uldum again. It’s just as awesome the second time around. Unfortunately, upon finishing it up, I have, once again, found myself at a loss for what to do.
Many people said the same thing about level 80 in Wrath. When you're leveling, there's a clear direction on what to do next. At max level, though, what do you do?
If you have fun doing daily quests, exploring zones that you skipped, and going for solo achievements, then reaching the level cap opens up a host of possibilities. You won't be bored. You will, however, have to approach the game differently than you did during levelling, which already runs people into a sort of options paralysis.
Things are different if you want to continue to make your character more powerful. You have to increase reputation with factions that will give your character better gear. You need to run a random heroic once a day. You need to run randoms, heroic or otherwise, until you have at least 333 gear in most slots, either through drops or through justice points. You need to get your professions up to max level. It's a lot of different things, and you have to direct yourself to know to do them, and you don't get the clearcut goals and dings from the default UI to guide you on the path.
In addition, you need to run raids. Raids in Cataclysm are less forgiving than in Wrath. I don't just mean the first-tier raid, either. Naxxramus was notoriously easy, but Ulduar, Trial, and Icecrown were all manageable if you maxxed out gear from the previous tear. To contrast, trying to do Cataclysm raids in mostly ilvl-333 gear is going to be painful. Lots of fights are going to be balanced such that you must do everything exactly perfectly or the healers will run out of mana or you'll miss the enrage timer or some other problem.
To my taste, the intro raids are balanced a little bit too difficult in Cataclysm. I wish they had at least a few raiding bosses that were pretty easy, so that less organized guilds could at least do the easy bosses every week and gear up slowly. More dedicate guilds would be coordinated enough to beat the harder bosses every week, too, so they'd advance much more quickly.