I love playing around with house rules, and I came up with the following to address some of my hangups with the SIEGE engine. My basic issues are thus:
1) The 12/18 challenge base for primes vs non-primes is too great
2) Classes without a prime attribute in one or more of their abilities (non-human rangers can't have primes in all of their class abilities, for example)
3) Adding your level to tests creates significant disparities as you increase in level

Please note that these are my hangups, and I'm not suggesting these are universal problems. So I respectfully ask that we not debate whether these are, in fact, actual problems.

Here is a solution that I rather like:

Challenge Base is 10 for every test, save combat attacks (where Base to Hit and AC values remain as in the RAW).

Challenge level is ranked on a 0-10 scale. In cases where the CL is based on a spell or monster’s HD, use half the value rounded up. For example, a creature with 5 HD would pose a CL of 3. A saving throw against a 7th level spell would face a CL of 4.

Using these limitations insures Challenge Classes have an upper limit of 20.

Each attribute has three modifiers: base, prime, and class.

Base modifiers are ranked on the standard -3 to +3 scale.

Prime modifiers equal the base modifier +2.

Class modifiers equal the prime modifier plus 2 to 5, depending on the character’s level (see below). Class modifiers are used when the test is directly related to the character’s class (a ranger tracking or a rogue picking a pocket, for example).

Using these values limits attribute modifiers to +10 without magical means.



For example:

A 4th level bard with STR 10, DEX 13, CON 11, INT 15, WIS 7, CHA 17 and primes in DEX and CHA would have an attribute modifier breakdown like this:


Since this character is a bard, any of his class abilities using CHA would receive a +7 bonus to his d20 test rolls. Since DEX is not used in any bard abilities, he would not use his class modifier for DEX rolls unless the CK makes an exception; for example, perhaps the bard is attempting to play his lute for a king. Playing a musical instrument seems like something a bard should be able to do, so the CK grants the player the use of his class modifier.

In play, the CK will ask for either a prime or class-based roll.

There might be a slight amount more time involved in chargen using this process, but I believe it would be very efficient in play. I like that primes aren't as powerful as in the RAW, and that all class abilities would never be overshadowed by another character with a prime attribute that outclassed the skilled character. Anyways, I hope it has some merit. Now to test it out...

First off, Kudos! Have you looked at the chances of success across your limited range? I was thinking of hacking the crap out of C&C before I decided to just run it. I cooked up some tables of odds I can share with you if you like. You can extrapolate your odds from them and adjust if needed.

Quote from: trechriron;957476First off, Kudos! Have you looked at the chances of success across your limited range? I was thinking of hacking the crap out of C&C before I decided to just run it. I cooked up some tables of odds I can share with you if you like. You can extrapolate your odds from them and adjust if needed.

I would be very interested in seeing what you have created!