With Fourth Edition less than two months away at this point, a lot of DM's with long standing campaigns are faced with a quandary. To convert or not to convert?
I have to admit that I lucked out when it was time to convert from Second Edition to Third Edition. On the week the Third Edition PHB came out, the entire party was killed. Since everyone was agreeable, we continued the same campaign with new characters created for the new edition. So the problem was neatly avoided.
Since a TPK (Total Party Kill) is probably not the route most people want to take when converting, I should look at some of the other options a DM might take.
At least one of the DM's I game with has stated it is unlikely that he will convert his current game over. He figures Third Edition was good enough for this game so far, and it will be good enough in the future.
There are definitely advantages to waiting. If you're party contains a tenth level half-dragon/half-ogre chaos monk/ur-priest/sacred fist there is not going to be a lot of support on day one. Probably not a lot of support on day one thousand for that combo!
Another tactic is to start a slow conversion. Start introducing the less intrusive rules until over time conversion is not that big of a deal. This is actually how my current gaming group converted from 3.0 to 3.5, where old PC's were grandfathered in but new PC's and NPC's switched over.
A slow conversion can be made to work on a story level too. Maybe Dragonborn start to filter into the game world from a distant kingdom that recently opened up trade routes! Maybe the stars align for the first time in ten millennia and the Feywild reconnects with your world, bringing Eladrin and other new forms of fey with it!
The downside to this is there is a painful middle period where your game is neither fish nor fowl. The fuzzy logic needed to navigate the game during this period can drive rules lawyers up a wall.
Of course, you can just bite the bullet and convert the best you can. This may take some creative reinterpretation of existing characters, especially if they belong to races or classes that no longer exist. You may not be a monk anymore, but with the right combo of classes and feats you are a hell of an unarmed combatant!
This leaves the question of how to deal with game world changes. Some DM's prefer the apocalyptic option. "Well, it looks like the gods fell to earth and when the returned to power it merged two realities. So that is why we have Tiefling running around!" On the other hand, some DM's prefer the hand waving/nothing to see here approach. "Of course there have always been Dragonborn around. Why do you even ask?"
So after this you might ask how I am handling the conversion question. Well, right now I am not running a game, so I will probably just start one fresh.
w00t! I win again!