d20 UTH - Save/Defense progression

I've been chewing on the rules and math behind saves, which become defenses in 4e. The current system involves charts. Look at the charts for all of your classes at the appropriate levels and add the bonuses. While it can involve some page flipping for multiclass characters the math isn't hard. But as characters level the disparities increase, plus there's the whole wackiness of multiclassing to get some stacked bonuses.

In the new generation (which includes Star Wars Saga Edition), save progression is flat. You get initial bonuses based on class, plus a flat bonus equal to half your level. If you multiclass you get the best bonus, not stacked bonuses.

Math crunchiness after the jump...


Let's look at three iconic (and save simple classes): fighter, rogue and wizard. Each is strong in a single save and weak in the other two. First let's look at the progression across a few levels for strong and weak saves...

Level * Strong * Weak * Difference
1 +2 +0 2
4 +4 +1 3
8 +6 +2 4
12 +8 +4 4
16 +10 +5 5
20 +12 +6 6

Now this part makes an assumption, that 4e will model the SWSE (save) defense progression. This means that the classes would get a +2 in their strong and +0 in their weak. Though the math is easy, so is copy and paste with a little editing...

Level * Strong * Weak * Difference
1 +2 +0 2
4 +4 +2 2
8 +6 +4 2
12 +8 +6 2
16 +10 +8 2
20 +12 +10 2

This makes it easier for a GM to pick the values of attacks like enemy spells and poisons. Under the old rules, at 8th level, a DC 15 (Fortitude) poison meant that a fighter needed a 9+ on d20 to save, while his wizard and rogue buddies needed 13+. That's 20%. Under the new, it is only a 10% swing (+2). While the fighter is still more likely to unaffected, it now isn't an increasingly larger chance.

Multiclassing skews save progression under the old system because of stacking. Let's look at a 7th level cleric with a level of fighter thrown in the mix (maybe he worships a war god).

Fort Ref Will
+7 +2 +5

That makes his strongest swing +5 from his weakest. Under the new system...

Fort Ref Will
+6 +4 +6

Yes, power-gamer types will hate these new rules. I'm finding them pretty acceptable as I start chewing on converting d20 Modern to 4e/SWSE for a campaign setting I call the Accords of Mil.