One problem that usually comes with GMing any successful RPG line  is rules bloat. Unless you’re running Call of Cthulhu (and I’m certain there are others), your successful RPG probably has several splatbooks that increase player character options. While many of these options are inspiring and help flesh out characters, they also tend to create headaches in terms of game balance, especially when you forget that Encounter #17 can be easily defeated by Advantage #32 in the Complete Guide to GM-Screwing III.

A solution that works for me is to stick to the core rules.

The core rules of any well-designed game have been extensively balanced and playtested. The PCs generated are designed to overcome the challenges that the game offers and there are usually more than enough options for the players to choose from so that no two PCs are alike or stepping on each other’s toes.

The flip side, of course, is that players love options and if you don’t allow character options from the Unbalanced Third Party Product that Nonetheless has Really Kewl Powerz then you’re likely to get some resistance. Sometimes the player begs, grovels, or holds your puppy hostage until you allow such a product into the game, opening the floodgates to more such options.

Here are a few reasons I’ve collected over the years in support of sticking to the core:

Adventures are generally written with the core books in mind.

Sure your favorite game line might have over 30 books, but chances are that the adventures are written so that you only need the core rules to play. This is intentional, as the publishers want to cast as wide a net as possible for GMs to buy their adventures. Requiring that new GMs (and even old ones) purchase 6 or 7 books before they can make use of an adventure is a good way to not sell a lot of adventures.

Coupled with this is balance. If the adventure designer is limited to the core books, then she usually isn’t worried about the crunch in other supplements when plotting her adventure. This increases the probability that a party of splatbook empowered PCs can run roughshod over what were meant to be intense encounters.

Supplements usually introduce power creep.

The more crunch that is produced, the more niche the crunch becomes, usually with a corresponding increase in power. In D&D 3.x, making a decent fighter/wizard combination required lots of trade-offs and the resulting character was nowhere near as good as a regular fighter or wizard. Enter the splatbooks and suddenly there are dozens of fighter/wizard combos in which this is no longer true. Maybe the fighter/wizard doesn’t have proficiency in the breadth of weapons a normal fighter does and maybe his spell list is a bit more limited than a true wizard, but does it matter mechanically if he still has the same attack bonus and caster level as his single-classed counterparts?

I said it above but it’s worth repeating; by sticking to the core you are using the most balanced set of rules. PCs will have less of a tendency to step into others’ niches or cause headaches when they unleash over-powered abilities.

Allowing Supplements may actually limit player options and creativity.

I once ran a 7th Sea campaign not long after the rules and the first few splatbooks had come out. I had a policy of allowing splatbooks at the time and I noticed that my players wouldn’t make characters of a particular nationality or secret society unless the supplement was available (indeed, I had some players pestering me on when I was going to be able to get particular supplements so they could play those characters). I remember a similar experience back when the AD&D 2e class handbooks (the ones with the “kits”) came out.

In addition, having the players “make do” with the core rules usually results in less “cookie-cutter” characters. To pick on D&D again, back in the “basic” days the “fighter” class represented all characters with a martial bent, whether you wanted to portray her as a barbarian, noble knight, roguish swashbuckler, mercenary soldier, or wilderness hunter. Once you start allowing classes that are tailored to some of those niches, players tend to look for appropriate classes in other splatbooks or abandon their concepts rather than use one that is a “poor fit.”

Too much crunch may result in too many specialists

I can’t tell you the number of times I’ve seen a party get stumped because the PC they relied on in a particular field lacked the skill/feat/power/class feature they needed because he was using a “substitute” version of an archetype that was tailored to a particular niche. This can certainly cause problems in published adventures if the “substitute” PCs are too easily exploited because they have weaknesses that weren’t taken into account.

Too many options slows the game down.

There’s nothing that’ll slow a game down more than if you need to reference and cross-reference seven rulebooks in a game session, especially when splatbooks conflict with each other (which is common after a game is launched and several splatbooks are being drafted at the same time). Similarly, a player that needs to create a character will spend far more time building her if she can flip through twelve books in order to do so.

Practical Reasons

Finally, there are practical reasons to keep the core books down. The first of these is cash. By limiting yourself to the core, you and your players don’t have to spend a lot of money to keep up with the game. The second of these is the floodgate. Once you allow a player to use one splatbook, you lose your moral high ground to prevent the next player from introducing another.

Also, if you don’t run the game out of your home then you’ll only need to lug a few books to the game. While advances in technology are making portabilitiy less of an issue, it’s always good to have a hard copy with you if the power goes out or you’re the only one with a laptop in front of you.

So those are a few of my reasons; how about you? Have you ever run a “core only” campaign using an RPG with splatbooks? If so, did you find it helpful or limiting? What other reasons do you have for sticking to the core or, on the flip side, allowing extra crunch?