Happy New Year everybody! I thought I’d start off this year by finishing off a series of posts from last year.  Here’s the first installment in that regard.

Last year, the latest edition of Dungeons & Dragons hit the shelves. One of the hopes for the new edition was that it would slim down the rules bloat from the previous edition. This is hardly unique; the latest version of the World of Darkness consolidated their slightly incompatible lines into a unified whole, GURPS consolidated their various rules into Compendia  (and, ultimately, a new edition), and previous versions of D&D also tightened up what had gone before.

The last edition of D&D was also cleaner and tighter than what had come before. In fact, if you played by only using the core rules (an assumption third party adventures had to make, as the “splatbooks” lacked open content), the game still runs smoothly today. That said, most D&D tables in the last few years weren’t so smooth, as official supplements (books put out by the publisher of a game) added new races, classes, feats, power subsystems and other options. A game run strictly by the core rules will play very differently than one using the Book of Nine Swords, warlock powers, and options from Unearthed Arcana.

The desire to add new material to your game is a strong one, especially when that supplement comes from the “official” source (even if it is considered optional). There is the danger, however, that a new supplement can take your campaigns into unwanted directions.

Here are a few warning signs:

1. Balance

It’s no secret that the most balanced version of a game is generally the core rules. These are the most extensively playtested rules and there is more of a “big picture” focus. More resources tend to go into a core book than its supplements.

2. New Subsystems

I’ve mentioned this before, but new supplements sometimes add new elements to a game that could threaten balance (see above) or how the game is played. The classic D&D example is psionics; another was the expanded combat rules for the old World of Darkness.

3. Stepping on a Niche

Sometimes official supplements will “nerf” a previous class’s abilities. How will the paladin’s player react to a crusader from the Book of Nine Swords? How would a Castillian hero in 7th Sea react to the Castille sourcebook, which adds new options and magic for heroes from his homeland, especially if a new hero joins the group that takes advantage of it? How does the sorcerer feel about that new warlock slinging eldritch bolts with wild abandon every round?

4. Power Creep

New options generally mean an increase in power, simply because there are more options to choose from that enable rules to stack in brutally efficient ways. A wizard using the spells in the basic set of GURPS (3e) will certainly be outclassed by one using spells from Magic and Grimoire.

5. Planning Challenges

It’s easier to design adventures if you know what your party is capable of. In D&D, this was the classic Four Food Groups (see Gnomenclature). Add too many official supplements and it gets harder to judge how to design adventures (who among us hasn’t seen the shocked look on a GM’s face when a player nerfs her Big Bad with a power she didn’t realize existed?).

6. Kewlness Factor

Supplements are designed to attract attention. This increases the possibility of them being “broken.” Use your players as a guide; if the new element is a variant of an old (a new type of controller, for example), and everyone wants to play it to the point of not wanting to play the old anymore, chances are that the new element is broken.

Overall, my best advice is to treat any official supplement as potential house rules. Don’t let them into your game without giving them a good read-through, and let your players know that, if you allow it, you won’t hesitate to pull it if it proves damaging to your campaign (no matter whose name is on the cover).