As you know, the Cataclysm is going to bring major changes to the whole world of Azeroth. There will only be 5 new zones for leveling above 80 and one new zone for each new race -- the rest of the work they're doing involves changing the old zones, bringing them up to the standards of zones in The Burning Crusade and Wrath of the Lich King, adding new quests that are more appropriate to the current timeline, and completely rebuilding the areas that just didn't work so well.
You are also probably aware that this is a much-needed improvement. The 1 - 60 leveling process (except for the draenei or blood elf starting areas) has long been fraught with serious flaws. Going through it the first time wasn't so bad, since exploring everything felt so new, but doing it the third and fourth times meant sheer boredom. I remember many times going to a zone, completing many or all of the quests there, and leaving without ever feeling as though I had really "been" there. Except for a few real gems, quests mostly involved spending a lot of time running long distances in order to kill more nameless bad guys -- they felt more like pest control than adventure. Just being there seemed to remove me from the story of Azeroth, and dump me in some other world where there was nothing important happening. Vast stretches of land on the Azeroth map meant absolutely nothing to me as a roleplayer: no character, no story, no meaning.
Getting to Outland, however, opened a new chapter, even if you had done the quests there before and new there was nothing new to see, they still felt like an actual "experience" of some kind. They flowed more in the manner of an actual story, and by the time you finished a zone, Hellfire Peninsula for example, you felt as though you had "been to Hellfire" and done what people do there. You didn't just deliver messages, kill a few monsters that happened to be lurking in and around nearby caves, and pick up random objects from the ground lying near yet another set of nondescript ruins -- you could exorcise a possessed comrade, make first contact with a lost orcish clan, or uncover the horrifying story behind the Path of Glory. Most of the quests involved you in the area so much that it began to feel like a real environment where things actually happened.
And of course, ever since Wrath was released, players keep coming back to the death knight starting area over and over again, partly because the phasing and storytelling were so nice, but also because it was structured so nicely -- every advancement in the quest line was a natural part of an overarching experience that had a beginning, middle and end, and nothing left you feeling as though you were doing a whole lot of running around for no real purpose. Even if you now the story by heart, you know you're progressing through something that defines your character, not just running errands.
And that is exactly what we have always hoped the rest of the world could be like. If the Cataclysm expansion lives up to our expectations, then perhaps all of Azeroth will be as engaging as Outland and Northrend have been.
Return of the Alt
Of course the whole point of making the old Azeroth new again is so that we can create new characters to enjoy it with. Many roleplayers are already altoholics -- not all of them of course, but lots of them have way too many character ideas. Often we don't like sitting in one skin for too long, and we may even have a whole troupe of characters with all manner of interconnections who interact with our guild members and friends in different ways. Often each of our guildmates has such characters too, and... well, it all gets very complicated.
I, too, started down this path some time ago, but I have since restrained myself to just a few of my favorite characters, usually spread out on multiple servers so that I can have more diverse experiences with each one of them. Until news broke of the Cataclysm, I had completely given up leveling any new character from scratch, no matter how much I wanted to roleplay them. I tried restricting my new characters to death knights, since they can skip most of the old world, but that has also limited my creativity somewhat.
But now that is about to change. Not only will I be eager to try out new goblin and worgen characters, but I wouldn't be surprised if I ended up trying some other combination as well. Undoubtedly that is one of Blizzard's main motivations behind the new races, the new class combinations, and the revamp of Azeroth as a whole -- they want the process of going from 1 to the level cap to be one we can enjoy many times over.
Alt epidemic threat level: Orange
However, some might argue that roleplayers generally have too many characters already, and adding more is only going to make the roleplaying environment worse. The main problem with having lots of alts is that it can be so hard to keep track of them all. It's easy to get confused about which alt belongs to which of your friends unless you are in a dedicated RP guild and keep current with all the latest stories going on in your group. If, like me, you've been forced to take breaks for a while, it can be very disorienting to come back to your old guild and not recognize many of the new names there, because old friends have gone and made new characters while you were away. With all the new characters people will be making when Cataclysm comes around, roleplayers will have to pay close attention to avoid getting confused.
Another downside to having so many characters is that it's hard to find time to give them all the time they may deserve. I know from experience how starting even just one new character makes it easy to neglect the old ones, and for roleplayers that can mean neglecting all the relationships those characters have developed as well. Once a character is gone for too long, it's not easy to bring him or her back into the roleplayers' milieu once again -- you get a feeling that everyone around you has moved on, while this character has remained stagnant. You may try to think of reasons to explain their long absence, but often these feel rather flat, more like excuses than actual stories.
On the other hand, maybe this tendency to drift from character to character rather than try to maintain many alts is a good one; in fiction, after all, character's stories have beginnings, middles, and ends. Perhaps the characters we roleplay should go through these stages as well, so that we keep things fresh for ourselves.
Whatever we do, the question of new characters, whether they are alts or new mains, is one that will affect roleplayers now more than ever. Cataclysm will surely shake up the roleplaying world as much as it does everything else. We must choose which new characters to conjure up, which ones to kill off in a blaze of glory, and which ones to simply ignore as they fade away from memory, lost to the clouds of time.